603 lines
21 KiB
JavaScript
603 lines
21 KiB
JavaScript
/*
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* Copyright 2012, Mozilla Foundation and contributors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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"use strict";
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/* globals document */
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/**
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* For full documentation, see:
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* https://github.com/mozilla/domtemplate/blob/master/README.md
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*/
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/**
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* Begin a new templating process.
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* @param node A DOM element or string referring to an element's id
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* @param data Data to use in filling out the template
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* @param options Options to customize the template processing. One of:
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* - allowEval: boolean (default false) Basic template interpolations are
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* either property paths (e.g. ${a.b.c.d}), or if allowEval=true then we
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* allow arbitrary JavaScript
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* - stack: string or array of strings (default empty array) The template
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* engine maintains a stack of tasks to help debug where it is. This allows
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* this stack to be prefixed with a template name
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* - blankNullUndefined: By default DOMTemplate exports null and undefined
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* values using the strings 'null' and 'undefined', which can be helpful for
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* debugging, but can introduce unnecessary extra logic in a template to
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* convert null/undefined to ''. By setting blankNullUndefined:true, this
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* conversion is handled by DOMTemplate
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*/
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var template = function (node, data, options) {
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let state = {
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options: options || {},
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// We keep a track of the nodes that we've passed through so we can keep
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// data.__element pointing to the correct node
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nodes: []
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};
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state.stack = state.options.stack;
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if (!Array.isArray(state.stack)) {
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if (typeof state.stack === "string") {
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state.stack = [ options.stack ];
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} else {
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state.stack = [];
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}
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}
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processNode(state, node, data);
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};
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if (typeof exports !== "undefined") {
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exports.template = template;
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}
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this.template = template;
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/**
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* Helper for the places where we need to act asynchronously and keep track of
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* where we are right now
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*/
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function cloneState(state) {
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return {
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options: state.options,
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stack: state.stack.slice(),
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nodes: state.nodes.slice()
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};
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}
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/**
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* Regex used to find ${...} sections in some text.
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* Performance note: This regex uses ( and ) to capture the 'script' for
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* further processing. Not all of the uses of this regex use this feature so
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* if use of the capturing group is a performance drain then we should split
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* this regex in two.
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*/
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var TEMPLATE_REGION = /\$\{([^}]*)\}/g;
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/**
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* Recursive function to walk the tree processing the attributes as it goes.
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* @param node the node to process. If you pass a string in instead of a DOM
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* element, it is assumed to be an id for use with document.getElementById()
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* @param data the data to use for node processing.
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*/
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function processNode(state, node, data) {
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if (typeof node === "string") {
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node = document.getElementById(node);
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}
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if (data == null) {
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data = {};
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}
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state.stack.push(node.nodeName + (node.id ? "#" + node.id : ""));
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let pushedNode = false;
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try {
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// Process attributes
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if (node.attributes && node.attributes.length) {
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// We need to handle 'foreach' and 'if' first because they might stop
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// some types of processing from happening, and foreach must come first
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// because it defines new data on which 'if' might depend.
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if (node.hasAttribute("foreach")) {
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processForEach(state, node, data);
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return;
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}
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if (node.hasAttribute("if")) {
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if (!processIf(state, node, data)) {
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return;
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}
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}
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// Only make the node available once we know it's not going away
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state.nodes.push(data.__element);
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data.__element = node;
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pushedNode = true;
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// It's good to clean up the attributes when we've processed them,
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// but if we do it straight away, we mess up the array index
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let attrs = Array.prototype.slice.call(node.attributes);
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for (let i = 0; i < attrs.length; i++) {
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let value = attrs[i].value;
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let name = attrs[i].name;
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state.stack.push(name);
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try {
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if (name === "save") {
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// Save attributes are a setter using the node
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value = stripBraces(state, value);
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property(state, value, data, node);
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node.removeAttribute("save");
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} else if (name.substring(0, 2) === "on") {
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// If this attribute value contains only an expression
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if (value.substring(0, 2) === "${" && value.slice(-1) === "}" &&
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value.indexOf("${", 2) === -1) {
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value = stripBraces(state, value);
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let func = property(state, value, data);
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if (typeof func === "function") {
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node.removeAttribute(name);
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let capture = node.hasAttribute("capture" + name.substring(2));
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node.addEventListener(name.substring(2), func, capture);
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if (capture) {
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node.removeAttribute("capture" + name.substring(2));
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}
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} else {
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// Attribute value is not a function - use as a DOM-L0 string
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node.setAttribute(name, func);
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}
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} else {
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// Attribute value is not a single expression use as DOM-L0
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node.setAttribute(name, processString(state, value, data));
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}
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} else {
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node.removeAttribute(name);
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// Remove '_' prefix of attribute names so the DOM won't try
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// to use them before we've processed the template
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if (name.charAt(0) === "_") {
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name = name.substring(1);
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}
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// Async attributes can only work if the whole attribute is async
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let replacement;
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if (value.indexOf("${") === 0 &&
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value.charAt(value.length - 1) === "}") {
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replacement = envEval(state, value.slice(2, -1), data, value);
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if (replacement && typeof replacement.then === "function") {
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node.setAttribute(name, "");
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/* jshint loopfunc:true */
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replacement.then(function (newValue) {
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node.setAttribute(name, newValue);
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}).then(null, console.error);
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} else {
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if (state.options.blankNullUndefined && replacement == null) {
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replacement = "";
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}
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node.setAttribute(name, replacement);
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}
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} else {
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node.setAttribute(name, processString(state, value, data));
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}
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}
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} finally {
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state.stack.pop();
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}
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}
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}
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// Loop through our children calling processNode. First clone them, so the
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// set of nodes that we visit will be unaffected by additions or removals.
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let childNodes = Array.prototype.slice.call(node.childNodes);
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for (let j = 0; j < childNodes.length; j++) {
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processNode(state, childNodes[j], data);
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}
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/* 3 === Node.TEXT_NODE */
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if (node.nodeType === 3) {
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processTextNode(state, node, data);
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}
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} finally {
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if (pushedNode) {
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data.__element = state.nodes.pop();
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}
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state.stack.pop();
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}
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}
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/**
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* Handle attribute values where the output can only be a string
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*/
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function processString(state, value, data) {
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return value.replace(TEMPLATE_REGION, function (path) {
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let insert = envEval(state, path.slice(2, -1), data, value);
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return state.options.blankNullUndefined && insert == null ? "" : insert;
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});
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}
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/**
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* Handle <x if="${...}">
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* @param node An element with an 'if' attribute
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* @param data The data to use with envEval()
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* @returns true if processing should continue, false otherwise
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*/
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function processIf(state, node, data) {
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state.stack.push("if");
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try {
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let originalValue = node.getAttribute("if");
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let value = stripBraces(state, originalValue);
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let recurse = true;
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try {
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let reply = envEval(state, value, data, originalValue);
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recurse = !!reply;
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} catch (ex) {
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handleError(state, "Error with '" + value + "'", ex);
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recurse = false;
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}
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if (!recurse) {
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node.parentNode.removeChild(node);
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}
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node.removeAttribute("if");
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return recurse;
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} finally {
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state.stack.pop();
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}
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}
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/**
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* Handle <x foreach="param in ${array}"> and the special case of
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* <loop foreach="param in ${array}">.
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* This function is responsible for extracting what it has to do from the
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* attributes, and getting the data to work on (including resolving promises
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* in getting the array). It delegates to processForEachLoop to actually
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* unroll the data.
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* @param node An element with a 'foreach' attribute
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* @param data The data to use with envEval()
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*/
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function processForEach(state, node, data) {
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state.stack.push("foreach");
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try {
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let originalValue = node.getAttribute("foreach");
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let value = originalValue;
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let paramName = "param";
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if (value.charAt(0) === "$") {
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// No custom loop variable name. Use the default: 'param'
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value = stripBraces(state, value);
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} else {
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// Extract the loop variable name from 'NAME in ${ARRAY}'
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let nameArr = value.split(" in ");
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paramName = nameArr[0].trim();
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value = stripBraces(state, nameArr[1].trim());
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}
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node.removeAttribute("foreach");
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try {
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let evaled = envEval(state, value, data, originalValue);
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let cState = cloneState(state);
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handleAsync(evaled, node, function (reply, siblingNode) {
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processForEachLoop(cState, reply, node, siblingNode, data, paramName);
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});
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node.parentNode.removeChild(node);
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} catch (ex) {
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handleError(state, "Error with " + value + "'", ex);
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}
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} finally {
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state.stack.pop();
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}
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}
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/**
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* Called by processForEach to handle looping over the data in a foreach loop.
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* This works with both arrays and objects.
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* Calls processForEachMember() for each member of 'set'
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* @param set The object containing the data to loop over
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* @param templNode The node to copy for each set member
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* @param sibling The sibling node to which we add things
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* @param data the data to use for node processing
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* @param paramName foreach loops have a name for the parameter currently being
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* processed. The default is 'param'. e.g. <loop foreach="param in ${x}">...
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*/
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function processForEachLoop(state, set, templNode, sibling, data, paramName) {
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if (Array.isArray(set)) {
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set.forEach(function (member, i) {
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processForEachMember(state, member, templNode, sibling,
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data, paramName, "" + i);
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});
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} else {
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for (let member in set) {
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if (set.hasOwnProperty(member)) {
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processForEachMember(state, member, templNode, sibling,
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data, paramName, member);
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}
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}
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}
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}
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/**
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* Called by processForEachLoop() to resolve any promises in the array (the
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* array itself can also be a promise, but that is resolved by
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* processForEach()). Handle <LOOP> elements (which are taken out of the DOM),
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* clone the template node, and pass the processing on to processNode().
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* @param member The data item to use in templating
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* @param templNode The node to copy for each set member
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* @param siblingNode The parent node to which we add things
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* @param data the data to use for node processing
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* @param paramName The name given to 'member' by the foreach attribute
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* @param frame A name to push on the stack for debugging
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*/
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function processForEachMember(state, member, templNode, siblingNode, data,
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paramName, frame) {
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state.stack.push(frame);
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try {
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let cState = cloneState(state);
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handleAsync(member, siblingNode, function (reply, node) {
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// Clone data because we can't be sure that we can safely mutate it
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let newData = Object.create(null);
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Object.keys(data).forEach(function (key) {
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newData[key] = data[key];
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});
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newData[paramName] = reply;
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if (node.parentNode != null) {
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let clone;
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if (templNode.nodeName.toLowerCase() === "loop") {
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for (let i = 0; i < templNode.childNodes.length; i++) {
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clone = templNode.childNodes[i].cloneNode(true);
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node.parentNode.insertBefore(clone, node);
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processNode(cState, clone, newData);
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}
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} else {
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clone = templNode.cloneNode(true);
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clone.removeAttribute("foreach");
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node.parentNode.insertBefore(clone, node);
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processNode(cState, clone, newData);
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}
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}
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});
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} finally {
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state.stack.pop();
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}
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}
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/**
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* Take a text node and replace it with another text node with the ${...}
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* sections parsed out. We replace the node by altering node.parentNode but
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* we could probably use a DOM Text API to achieve the same thing.
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* @param node The Text node to work on
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* @param data The data to use in calls to envEval()
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*/
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function processTextNode(state, node, data) {
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// Replace references in other attributes
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let value = node.data;
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// We can't use the string.replace() with function trick (see generic
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// attribute processing in processNode()) because we need to support
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// functions that return DOM nodes, so we can't have the conversion to a
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// string.
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// Instead we process the string as an array of parts. In order to split
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// the string up, we first replace '${' with '\uF001$' and '}' with '\uF002'
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// We can then split using \uF001 or \uF002 to get an array of strings
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// where scripts are prefixed with $.
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// \uF001 and \uF002 are just unicode chars reserved for private use.
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value = value.replace(TEMPLATE_REGION, "\uF001$$$1\uF002");
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// Split a string using the unicode chars F001 and F002.
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let parts = value.split(/\uF001|\uF002/);
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if (parts.length > 1) {
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parts.forEach(function (part) {
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if (part === null || part === undefined || part === "") {
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return;
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}
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if (part.charAt(0) === "$") {
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part = envEval(state, part.slice(1), data, node.data);
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}
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let cState = cloneState(state);
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handleAsync(part, node, function (reply, siblingNode) {
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let doc = siblingNode.ownerDocument;
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if (reply == null) {
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reply = cState.options.blankNullUndefined ? "" : "" + reply;
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}
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if (typeof reply.cloneNode === "function") {
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// i.e. if (reply instanceof Element) { ...
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reply = maybeImportNode(cState, reply, doc);
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siblingNode.parentNode.insertBefore(reply, siblingNode);
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} else if (typeof reply.item === "function" && reply.length) {
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// NodeLists can be live, in which case maybeImportNode can
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// remove them from the document, and thus the NodeList, which in
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// turn breaks iteration. So first we clone the list
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let list = Array.prototype.slice.call(reply, 0);
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list.forEach(function (child) {
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let imported = maybeImportNode(cState, child, doc);
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siblingNode.parentNode.insertBefore(imported, siblingNode);
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});
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} else {
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// if thing isn't a DOM element then wrap its string value in one
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reply = doc.createTextNode(reply.toString());
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siblingNode.parentNode.insertBefore(reply, siblingNode);
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}
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});
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});
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node.parentNode.removeChild(node);
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}
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}
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/**
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* Return node or a import of node, if it's not in the given document
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* @param node The node that we want to be properly owned
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* @param doc The document that the given node should belong to
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* @return A node that belongs to the given document
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*/
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function maybeImportNode(state, node, doc) {
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return node.ownerDocument === doc ? node : doc.importNode(node, true);
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}
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/**
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* A function to handle the fact that some nodes can be promises, so we check
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* and resolve if needed using a marker node to keep our place before calling
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* an inserter function.
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* @param thing The object which could be real data or a promise of real data
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* we use it directly if it's not a promise, or resolve it if it is.
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* @param siblingNode The element before which we insert new elements.
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* @param inserter The function to to the insertion. If thing is not a promise
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* then handleAsync() is just 'inserter(thing, siblingNode)'
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*/
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function handleAsync(thing, siblingNode, inserter) {
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if (thing != null && typeof thing.then === "function") {
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// Placeholder element to be replaced once we have the real data
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let tempNode = siblingNode.ownerDocument.createElement("span");
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siblingNode.parentNode.insertBefore(tempNode, siblingNode);
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thing.then(function (delayed) {
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inserter(delayed, tempNode);
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if (tempNode.parentNode != null) {
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tempNode.parentNode.removeChild(tempNode);
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}
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}).then(null, function (error) {
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console.error(error.stack);
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});
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} else {
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inserter(thing, siblingNode);
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}
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}
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/**
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* Warn of string does not begin '${' and end '}'
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* @param str the string to check.
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* @return The string stripped of ${ and }, or untouched if it does not match
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*/
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function stripBraces(state, str) {
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if (!str.match(TEMPLATE_REGION)) {
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handleError(state, "Expected " + str + " to match ${...}");
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return str;
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}
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return str.slice(2, -1);
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}
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/**
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* Combined getter and setter that works with a path through some data set.
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* For example:
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* <ul>
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* <li>property(state, 'a.b', { a: { b: 99 }}); // returns 99
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* <li>property(state, 'a', { a: { b: 99 }}); // returns { b: 99 }
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* <li>property(state, 'a', { a: { b: 99 }}, 42); // returns 99 and alters the
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* input data to be { a: { b: 42 }}
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* </ul>
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* @param path An array of strings indicating the path through the data, or
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* a string to be cut into an array using <tt>split('.')</tt>
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* @param data the data to use for node processing
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* @param newValue (optional) If defined, this value will replace the
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* original value for the data at the path specified.
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|
* @return The value pointed to by <tt>path</tt> before any
|
|
* <tt>newValue</tt> is applied.
|
|
*/
|
|
function property(state, path, data, newValue) {
|
|
try {
|
|
if (typeof path === "string") {
|
|
path = path.split(".");
|
|
}
|
|
let value = data[path[0]];
|
|
if (path.length === 1) {
|
|
if (newValue !== undefined) {
|
|
data[path[0]] = newValue;
|
|
}
|
|
if (typeof value === "function") {
|
|
return value.bind(data);
|
|
}
|
|
return value;
|
|
}
|
|
if (!value) {
|
|
handleError(state, "\"" + path[0] + "\" is undefined");
|
|
return null;
|
|
}
|
|
return property(state, path.slice(1), value, newValue);
|
|
} catch (ex) {
|
|
handleError(state, "Path error with '" + path + "'", ex);
|
|
return "${" + path + "}";
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Like eval, but that creates a context of the variables in <tt>env</tt> in
|
|
* which the script is evaluated.
|
|
* @param script The string to be evaluated.
|
|
* @param data The environment in which to eval the script.
|
|
* @param frame Optional debugging string in case of failure.
|
|
* @return The return value of the script, or the error message if the script
|
|
* execution failed.
|
|
*/
|
|
function envEval(state, script, data, frame) {
|
|
try {
|
|
state.stack.push(frame.replace(/\s+/g, " "));
|
|
// Detect if a script is capable of being interpreted using property()
|
|
if (/^[_a-zA-Z0-9.]*$/.test(script)) {
|
|
return property(state, script, data);
|
|
}
|
|
if (!state.options.allowEval) {
|
|
handleError(state, "allowEval is not set, however '" + script + "'" +
|
|
" can not be resolved using a simple property path.");
|
|
return "${" + script + "}";
|
|
}
|
|
|
|
// What we're looking to do is basically:
|
|
// with(data) { return eval(script); }
|
|
// except in strict mode where 'with' is banned.
|
|
// So we create a function which has a parameter list the same as the
|
|
// keys in 'data' and with 'script' as its function body.
|
|
// We then call this function with the values in 'data'
|
|
let keys = allKeys(data);
|
|
let func = Function.apply(null, keys.concat("return " + script));
|
|
|
|
let values = keys.map((key) => data[key]);
|
|
return func.apply(null, values);
|
|
|
|
// TODO: The 'with' method is different from the code above in the value
|
|
// of 'this' when calling functions. For example:
|
|
// envEval(state, 'foo()', { foo: function () { return this; } }, ...);
|
|
// The global for 'foo' when using 'with' is the data object. However the
|
|
// code above, the global is null. (Using 'func.apply(data, values)'
|
|
// changes 'this' in the 'foo()' frame, but not in the inside the body
|
|
// of 'foo', so that wouldn't help)
|
|
} catch (ex) {
|
|
handleError(state, "Template error evaluating '" + script + "'", ex);
|
|
return "${" + script + "}";
|
|
} finally {
|
|
state.stack.pop();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Object.keys() that respects the prototype chain
|
|
*/
|
|
function allKeys(data) {
|
|
let keys = [];
|
|
for (let key in data) {
|
|
keys.push(key);
|
|
}
|
|
return keys;
|
|
}
|
|
|
|
/**
|
|
* A generic way of reporting errors, for easy overloading in different
|
|
* environments.
|
|
* @param message the error message to report.
|
|
* @param ex optional associated exception.
|
|
*/
|
|
function handleError(state, message, ex) {
|
|
logError(message + " (In: " + state.stack.join(" > ") + ")");
|
|
if (ex) {
|
|
logError(ex);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* A generic way of reporting errors, for easy overloading in different
|
|
* environments.
|
|
* @param message the error message to report.
|
|
*/
|
|
function logError(message) {
|
|
console.error(message);
|
|
}
|
|
|
|
exports.template = template;
|