8ee50178f3
Correct: `Array.from()` (it’s a static method) Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method) This patch uses the common `#` syntax to denote `.prototype.`.
23 lines
735 B
Markdown
23 lines
735 B
Markdown
### bindKey
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Creates a function that invokes the method at a given key of an object, optionally adding any additional supplied parameters to the beginning of the arguments.
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Return a `function` that uses `Function.prototype.apply()` to bind `context[fn]` to `context`.
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Use the spread operator (`...`) to prepend any additional supplied parameters to the arguments.
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```js
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const bindKey = (context, fn, ...boundArgs) => (...args) =>
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context[fn].apply(context, [...boundArgs, ...args]);
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```
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```js
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const freddy = {
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user: 'fred',
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greet: function(greeting, punctuation) {
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return greeting + ' ' + this.user + punctuation;
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}
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};
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const freddyBound = bindKey(freddy, 'greet');
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console.log(freddyBound('hi', '!')); // 'hi fred!'
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```
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