overwriteMethod.js
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/*!
* Chai - overwriteMethod utility
* Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
* MIT Licensed
*/
/**
* ### overwriteMethod (ctx, name, fn)
*
* Overwites an already existing method and provides
* access to previous function. Must return function
* to be used for name.
*
* utils.overwriteMethod(chai.Assertion.prototype, 'equal', function (_super) {
* return function (str) {
* var obj = utils.flag(this, 'object');
* if (obj instanceof Foo) {
* new chai.Assertion(obj.value).to.equal(str);
* } else {
* _super.apply(this, arguments);
* }
* }
* });
*
* Can also be accessed directly from `chai.Assertion`.
*
* chai.Assertion.overwriteMethod('foo', fn);
*
* Then can be used as any other assertion.
*
* expect(myFoo).to.equal('bar');
*
* @param {Object} ctx object whose method is to be overwritten
* @param {String} name of method to overwrite
* @param {Function} method function that returns a function to be used for name
* @name overwriteMethod
* @api public
*/
module.exports = function (ctx, name, method) {
var _method = ctx[name]
, _super = function () { return this; };
if (_method && 'function' === typeof _method)
_super = _method;
ctx[name] = function () {
var result = method(_super).apply(this, arguments);
return result === undefined ? this : result;
}
};