25 lines
780 B
Markdown
25 lines
780 B
Markdown
---
|
|
title: bindKey
|
|
tags: function,object,intermediate
|
|
---
|
|
|
|
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.
|
|
|
|
Return a `function` that uses `Function.prototype.apply()` to bind `context[fn]` to `context`.
|
|
Use the spread operator (`...`) to prepend any additional supplied parameters to the arguments.
|
|
|
|
```js
|
|
const bindKey = (context, fn, ...boundArgs) => (...args) =>
|
|
context[fn].apply(context, [...boundArgs, ...args]);
|
|
```
|
|
|
|
```js
|
|
const freddy = {
|
|
user: 'fred',
|
|
greet: function(greeting, punctuation) {
|
|
return greeting + ' ' + this.user + punctuation;
|
|
}
|
|
};
|
|
const freddyBound = bindKey(freddy, 'greet');
|
|
console.log(freddyBound('hi', '!')); // 'hi fred!'
|
|
``` |