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/**
* Based conceptually on the _.extend() function in underscore.js ( see http://documentcloud.github.com/underscore/#extend for more details )
* Copyright (C) 2012 Kurt Milam - http://xioup.com | Source: https://gist.github.com/1868955
*
* This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
**/
deepExtend = function(obj) {
var parentRE = /#{\s*?_\s*?}/,
slice = Array.prototype.slice,
hasOwnProperty = Object.prototype.hasOwnProperty;
_.each(slice.call(arguments, 1), function(source) {
for (var prop in source) {
if (hasOwnProperty.call(source, prop)) {
if (_.isUndefined(obj[prop]) || _.isFunction(obj[prop])) {
obj[prop] = source[prop];
}
else if (_.isString(source[prop]) && parentRE.test(source[prop])) {
if (_.isString(obj[prop])) {
obj[prop] = source[prop].replace(parentRE, obj[prop]);
}
}
else if (_.isArray(obj[prop]) || _.isArray(source[prop])){
if (!_.isArray(obj[prop]) || !_.isArray(source[prop])){
throw 'Error: Trying to combine an array with a non-array (' + prop + ')';
} else {
obj[prop] = _.reject(_.deepExtend(obj[prop], source[prop]), function (item) { return _.isNull(item);});
}
}
else if (_.isObject(obj[prop]) || _.isObject(source[prop])){
if (!_.isObject(obj[prop]) || !_.isObject(source[prop])){
throw 'Error: Trying to combine an object with a non-object (' + prop + ')';
} else {
obj[prop] = _.deepExtend(obj[prop], source[prop]);
}
} else {
obj[prop] = source[prop];
}
}
}
});
return obj;
};
/**
* Dependency: underscore.js ( http://documentcloud.github.com/underscore/ )
*
* Mix it in with underscore.js:
* _.mixin({deepExtend: deepExtend});
*
* Call it like this:
* var myObj = _.deepExtend(grandparent, child, grandchild, greatgrandchild)
*
* Notes:
* Keep it DRY.
* This function is especially useful if you're working with JSON config documents. It allows you to create a default
* config document with the most common settings, then override those settings for specific cases. It accepts any
* number of objects as arguments, giving you fine-grained control over your config document hierarchy.
*
* Special Features and Considerations:
* - parentRE allows you to concatenate strings. example:
* var obj = _.deepExtend({url: "www.example.com"}, {url: "http://#{_}/path/to/file.html"});
* console.log(obj.url);
* output: "http://www.example.com/path/to/file.html"
*
* - parentRE also acts as a placeholder, which can be useful when you need to change one value in an array, while
* leaving the others untouched. example:
* var arr = _.deepExtend([100, {id: 1234}, true, "foo", [250, 500]],
* ["#{_}", "#{_}", false, "#{_}", "#{_}"]);
* console.log(arr);
* output: [100, {id: 1234}, false, "foo", [250, 500]]
*
* - The previous example can also be written like this:
* var arr = _.deepExtend([100, {id:1234}, true, "foo", [250, 500]],
* ["#{_}", {}, false, "#{_}", []]);
* console.log(arr);
* output: [100, {id: 1234}, false, "foo", [250, 500]]
*
* - And also like this:
* var arr = _.deepExtend([100, {id:1234}, true, "foo", [250, 500]],
* ["#{_}", {}, false]);
* console.log(arr);
* output: [100, {id: 1234}, false, "foo", [250, 500]]
*
* - Array order is important. example:
* var arr = _.deepExtend([1, 2, 3, 4], [1, 4, 3, 2]);
* console.log(arr);
* output: [1, 4, 3, 2]
*
* - You can remove an array element set in a parent object by setting the same index value to null in a child object.
* example:
* var obj = _.deepExtend({arr: [1, 2, 3, 4]}, {arr: ["#{_}", null]});
* console.log(obj.arr);
* output: [1, 3, 4]
*
**/
@wulftone
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wulftone commented Feb 5, 2013

Added support for properties that are functions. Previously it got to the _.isObject check and tried to deepExtend it again, which of course is silly if the property is a function, so we need to check for isFunction before it gets there and take appropriate action.

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