Add better _.forIn support for legacy browsers.

Former-commit-id: a03ce4662021d6ac8ca12c4885a9c4718c227a30

build.js

@@ -1148,6 +1148,27 @@
     return source;
   }
 
+  /**
+   * Removes all `support.enumErrorProps` references from `source`.
+   *
+   * @private
+   * @param {String} source The source to process.
+   * @returns {String} Returns the modified source.
+   */
+  function removeSupportEnumErrorProps(source) {
+    source = removeSupportProp(source, 'enumErrorProps');
+
+    // remove `support.enumErrorProps` from `iteratorTemplate`
+    source = source.replace(getIteratorTemplate(source), function(match) {
+      return match
+        .replace(/(?: *\/\/.*\n)* *["'] *(?:<% *)?if *\(support\.enumErrorProps *(?:&&|\))(.+?}["']|[\s\S]+?<% *} *(?:%>|["'])).+/g, '')
+        .replace(/support\.enumErrorProps\s*\|\|\s*/g, '');
+    });
+
+    return source;
+  }
+
+
   /**
    * Removes all `support.enumPrototypes` references from `source`.
    *
@@ -1168,7 +1189,7 @@
     // remove `support.enumPrototypes` from `iteratorTemplate`
     source = source.replace(getIteratorTemplate(source), function(match) {
       return match
-        .replace(/(?: *\/\/.*\n)* *["'] *(?:<% *)?if *\(support\.enumPrototypes *(?:&&|\))[\s\S]+?<% *} *(?:%>|["']).+/g, '')
+        .replace(/(?: *\/\/.*\n)* *["'] *(?:<% *)?if *\(support\.enumPrototypes *(?:&&|\))(.+?}["']|[\s\S]+?<% *} *(?:%>|["'])).+/g, '')
         .replace(/support\.enumPrototypes\s*\|\|\s*/g, '');
     });
 
@@ -1249,7 +1270,9 @@
 
     // remove `support.nonEnumShadows` from `iteratorTemplate`
     source = source.replace(getIteratorTemplate(source), function(match) {
-      return match.replace(/(?: *\/\/.*\n)* *["']( *)<% *if *\(support\.nonEnumShadows[\s\S]+?["']\1<% *} *%>.+/, '');
+      return match
+        .replace(/\s*\|\|\s*support\.nonEnumShadows/, '')
+        .replace(/(?: *\/\/.*\n)* *["']( *)<% *if *\(support\.nonEnumShadows[\s\S]+?["']\1<% *} *%>.+/, '');
     });
 
     return source;
@@ -1986,6 +2009,7 @@
         source = removeSupportNodeClass(source);
 
         if (!isMobile) {
+          source = removeSupportEnumErrorProps(source);
           source = removeSupportEnumPrototypes(source);
           source = removeSupportNonEnumArgs(source);
 

build/pre-compile.js

@@ -13,6 +13,7 @@
     'callback',
     'className',
     'collection',
+    'conditions',
     'ctor',
     'ctorByClass',
     'errorClass',
@@ -36,8 +37,8 @@
     'objectTypes',
     'ownIndex',
     'ownProps',
-    'proto',
     'result',
+    'skipErrorProps',
     'skipProto',
     'source',
     'stringClass',
@@ -112,6 +113,7 @@
     'difference',
     'drop',
     'each',
+    'enumErrorProps',
     'enumPrototypes',
     'environment',
     'escape',
@@ -290,7 +292,7 @@
         string = string.slice(left.length);
       }
       // avoids removing the '\n' of the `stringEscapes` object
-      string = string.replace(/\[object |delete |else (?!{)|function | in |return\s+[\w"']|throw |typeof |use strict|var |@ |(["'])\\n\1|\\\\n|\\n|\s+/g, function(match) {
+      string = string.replace(/\[object |delete |else (?!{)|function | in | instanceof |return\s+[\w"']|throw |typeof |use strict|var |@ |(["'])\\n\1|\\\\n|\\n|\s+/g, function(match) {
         return match == false || match == '\\n' ? '' : match;
       });
       // unclip

lodash.js

@@ -191,6 +191,7 @@
         getPrototypeOf = reNative.test(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
         hasOwnProperty = objectProto.hasOwnProperty,
         push = arrayProto.push,
+        propertyIsEnumerable = objectProto.propertyIsEnumerable,
         setImmediate = context.setImmediate,
         setTimeout = context.setTimeout,
         toString = objectProto.toString;
@@ -346,6 +347,14 @@
        */
       support.argsClass = isArguments(arguments);
 
+      /**
+       * Detect if `name` or `message` properties of `Error.prototype` are
+       * enumerable by default. (IE < 9, Safari < 5.1)
+       *
+       * @type Boolean
+       */
+      support.enumErrorProps = propertyIsEnumerable.call(errorProto, 'message') || propertyIsEnumerable.call(errorProto, 'name');
+
       /**
        * Detect if `prototype` properties are enumerable by default.
        *
@@ -357,7 +366,7 @@
        * @memberOf _.support
        * @type Boolean
        */
-      support.enumPrototypes = ctor.propertyIsEnumerable('prototype');
+      support.enumPrototypes = propertyIsEnumerable.call(ctor, 'prototype');
 
       /**
        * Detect if `Function#bind` exists and is inferred to be fast (all but V8).
@@ -529,7 +538,7 @@
 
       // iterate over the array-like value
       '  while (++index < length) {\n' +
-      '    <%= loop %>\n' +
+      '    <%= loop %>;\n' +
       '  }\n' +
       '}\n' +
       'else {' +
@@ -541,7 +550,7 @@
       '  if (length && isArguments(iterable)) {\n' +
       '    while (++index < length) {\n' +
       "      index += '';\n" +
-      '      <%= loop %>\n' +
+      '      <%= loop %>;\n' +
       '    }\n' +
       '  } else {' +
       '  <% } %>' +
@@ -551,29 +560,37 @@
       "  var skipProto = typeof iterable == 'function';\n" +
       '  <% } %>' +
 
-      // iterate own properties using `Object.keys` if it's fast
+      // avoid iterating over `Error.prototype` properties in older IE and Safari
+      '  <% if (support.enumErrorProps || support.nonEnumShadows) { %>\n' +
+      '  var skipErrorProps = iterable === errorProto || iterable instanceof Error;\n' +
+      '  <% } %>' +
+
+      // define conditions used in the loop
+      '  <%' +
+      '    var conditions = [];' +
+      '    if (support.enumPrototypes) { conditions.push("!(skipProto && index == \'prototype\')"); }' +
+      '    if (support.enumErrorProps)  { conditions.push("!(skipErrorProps && (index == \'message\' || index == \'name\'))"); }' +
+      '  %>' +
+
+      // iterate own properties using `Object.keys`
       '  <% if (useHas && useKeys) { %>\n' +
       '  var ownIndex = -1,\n' +
       '      ownProps = objectTypes[typeof iterable] ? keys(iterable) : [],\n' +
       '      length = ownProps.length;\n\n' +
       '  while (++ownIndex < length) {\n' +
-      '    index = ownProps[ownIndex];\n' +
-      "    <% if (support.enumPrototypes) { %>if (!(skipProto && index == 'prototype')) {\n  <% } %>" +
-      '    <%= loop %>\n' +
-      '    <% if (support.enumPrototypes) { %>}\n<% } %>' +
+      '    index = ownProps[ownIndex];\n<%' +
+      "    if (conditions.length) { %>    if (<%= conditions.join(' && ') %>) {\n  <% } %>" +
+      '    <%= loop %>;' +
+      '    <% if (conditions.length) { %>\n    }<% } %>\n' +
       '  }' +
 
       // else using a for-in loop
       '  <% } else { %>\n' +
-      '  for (index in iterable) {<%' +
-      '    if (support.enumPrototypes || useHas) { %>\n    if (<%' +
-      "      if (support.enumPrototypes) { %>!(skipProto && index == 'prototype')<% }" +
-      '      if (support.enumPrototypes && useHas) { %> && <% }' +
-      '      if (useHas) { %>hasOwnProperty.call(iterable, index)<% }' +
-      '    %>) {' +
-      '    <% } %>\n' +
+      '  for (index in iterable) {\n<%' +
+      '    if (useHas) { conditions.push("hasOwnProperty.call(iterable, index)"); }' +
+      "    if (conditions.length) { %>    if (<%= conditions.join(' && ') %>) {\n  <% } %>" +
       '    <%= loop %>;' +
-      '    <% if (support.enumPrototypes || useHas) { %>\n    }<% } %>\n' +
+      '    <% if (conditions.length) { %>\n    }<% } %>\n' +
       '  }' +
 
       // Because IE < 9 can't set the `[[Enumerable]]` attribute of an
@@ -583,19 +600,15 @@
       '    <% if (support.nonEnumShadows) { %>\n\n' +
       '  if (iterable !== objectProto) {\n' +
       "    var ctor = iterable.constructor,\n" +
-      '        proto = ctor && ctor.prototype,\n' +
-      '        isProto = iterable === proto,\n' +
-      '        nonEnum = nonEnumProps[objectClass];\n\n' +
-      '    if (isProto) {\n' +
-      "      var className = iterable === stringProto ? stringClass : iterable === errorProto ? errorClass : toString.call(iterable),\n" +
-      '          nonEnum = nonEnumProps[iterable === (ctorByClass[className] && ctorByClass[className].prototype) ? className : objectClass];\n' +
-      '    }\n' +
+      '        isProto = iterable === (ctor && ctor.prototype),\n' +
+      '        className = iterable === stringProto ? stringClass : iterable === errorProto ? errorClass : toString.call(iterable),\n' +
+      '        nonEnum = nonEnumProps[className];\n' +
       '      <% for (k = 0; k < 7; k++) { %>\n' +
       "    index = '<%= shadowedProps[k] %>';\n" +
       '    if ((!(isProto && nonEnum[index]) && hasOwnProperty.call(iterable, index))<%' +
       '        if (!useHas) { %> || (!nonEnum[index] && iterable[index] !== objectProto[index])<% }' +
       '      %>) {\n' +
-      '      <%= loop %>\n' +
+      '      <%= loop %>;\n' +
       '    }' +
       '      <% } %>\n' +
       '  }' +