1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5/**
6 * @fileoverview This is a simple template engine inspired by JsTemplates
7 * optimized for i18n.
8 *
9 * It currently supports two handlers:
10 *
11 *   * i18n-content which sets the textContent of the element
12 *
13 *     <span i18n-content="myContent"></span>
14 *     i18nTemplate.process(element, {'myContent': 'Content'});
15 *
16 *   * i18n-values is a list of attribute-value or property-value pairs.
17 *     Properties are prefixed with a '.' and can contain nested properties.
18 *
19 *     <span i18n-values="title:myTitle;.style.fontSize:fontSize"></span>
20 *     i18nTemplate.process(element, {
21 *       'myTitle': 'Title',
22 *       'fontSize': '13px'
23 *     });
24 */
25
26var i18nTemplate = (function() {
27  /**
28   * This provides the handlers for the templating engine. The key is used as
29   * the attribute name and the value is the function that gets called for every
30   * single node that has this attribute.
31   * @type {Object}
32   */
33  var handlers = {
34    /**
35     * This handler sets the textContent of the element.
36     */
37    'i18n-content': function(element, attributeValue, obj) {
38      element.textContent = obj[attributeValue];
39    },
40
41    /**
42     * This handler adds options to a select element.
43     */
44    'i18n-options': function(element, attributeValue, obj) {
45      var options = obj[attributeValue];
46      options.forEach(function(values) {
47        var option = typeof values == 'string' ? new Option(values) :
48            new Option(values[1], values[0]);
49        element.appendChild(option);
50      });
51    },
52
53    /**
54     * This is used to set HTML attributes and DOM properties,. The syntax is:
55     *   attributename:key;
56     *   .domProperty:key;
57     *   .nested.dom.property:key
58     */
59    'i18n-values': function(element, attributeValue, obj) {
60      var parts = attributeValue.replace(/\s/g, '').split(/;/);
61      for (var j = 0; j < parts.length; j++) {
62        var a = parts[j].match(/^([^:]+):(.+)$/);
63        if (a) {
64          var propName = a[1];
65          var propExpr = a[2];
66
67          // Ignore missing properties
68          if (propExpr in obj) {
69            var value = obj[propExpr];
70            if (propName.charAt(0) == '.') {
71              var path = propName.slice(1).split('.');
72              var object = element;
73              while (object && path.length > 1) {
74                object = object[path.shift()];
75              }
76              if (object) {
77                object[path] = value;
78                // In case we set innerHTML (ignoring others) we need to
79                // recursively check the content
80                if (path == 'innerHTML') {
81                  process(element, obj);
82                }
83              }
84            } else {
85              element.setAttribute(propName, value);
86            }
87          } else {
88            console.warn('i18n-values: Missing value for "' + propExpr + '"');
89          }
90        }
91      }
92    }
93  };
94
95  var attributeNames = [];
96  for (var key in handlers) {
97    attributeNames.push(key);
98  }
99  var selector = '[' + attributeNames.join('],[') + ']';
100
101  /**
102   * Processes a DOM tree with the {@code obj} map.
103   */
104  function process(node, obj) {
105    var elements = node.querySelectorAll(selector);
106    for (var element, i = 0; element = elements[i]; i++) {
107      for (var j = 0; j < attributeNames.length; j++) {
108        var name = attributeNames[j];
109        var att = element.getAttribute(name);
110        if (att != null) {
111          handlers[name](element, att, obj);
112        }
113      }
114    }
115  }
116
117  return {
118    process: process
119  };
120})();
121