22 lines
736 B
Markdown
22 lines
736 B
Markdown
---
|
|
title: bind
|
|
tags: function,object,intermediate
|
|
---
|
|
|
|
Creates a function that invokes `fn` with a given context, optionally adding any additional supplied parameters to the beginning of the arguments.
|
|
|
|
Return a `function` that uses `Function.prototype.apply()` to apply the given `context` to `fn`.
|
|
Use `Array.prototype.concat()` to prepend any additional supplied parameters to the arguments.
|
|
|
|
```js
|
|
const bind = (fn, context, ...boundArgs) => (...args) => fn.apply(context, [...boundArgs, ...args]);
|
|
```
|
|
|
|
```js
|
|
function greet(greeting, punctuation) {
|
|
return greeting + ' ' + this.user + punctuation;
|
|
}
|
|
const freddy = { user: 'fred' };
|
|
const freddyBound = bind(greet, freddy);
|
|
console.log(freddyBound('hi', '!')); // 'hi fred!'
|
|
``` |