mirror of
https://github.com/chaijs/chai
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48 lines
1.3 KiB
JavaScript
48 lines
1.3 KiB
JavaScript
/*!
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* Chai - overwriteProperty utility
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* Copyright(c) 2012 Jake Luer <jake@alogicalparadox.com>
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* MIT Licensed
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*/
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/**
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* # overwriteProperty (ctx, name, fn)
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*
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* Overwites an already existing property getter and provides
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* access to previous value. Must return function to use as getter.
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*
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* utils.overwriteProperty(chai.Assertion, 'ok', function (_super) {
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* return function () {
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* var obj = utils.flag(this, 'object');
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* if (obj instanceof Foo) {
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* new chai.Assertion(obj.name).to.equal('bar');
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* } else {
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* _super.call(this);
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* }
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* }
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* });
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*
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* Then can be used as any other assertion.
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*
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* expect(myFoo).to.be.ok;
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*
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* @param {Function|Object} context chai.Assertion || chai.Assertion.prototype
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* @param {String} name of property to overwrite
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* @param {Function} method must return function to be used for name
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* @api public
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*/
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module.exports = function (ctx, name, getter) {
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var _get = Object.getOwnPropertyDescriptor(ctx, name)
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, _super = function () {};
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if (_get && 'function' === typeof _get.get)
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_super = _get.get
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Object.defineProperty(ctx, name,
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{ get: function () {
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getter(_super).call(this);
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return this;
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}
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, configurable: true
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});
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};
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