30 lines
917 B
Markdown
30 lines
917 B
Markdown
---
|
|
title: functions
|
|
tags: object,function,advanced
|
|
---
|
|
|
|
Gets an array of function property names from own (and optionally inherited) enumerable properties of an object.
|
|
|
|
- Use `Object.keys(obj)` to iterate over the object's own properties.
|
|
- If `inherited` is `true`, use `Object.getPrototypeOf(obj)` to also get the object's inherited properties.
|
|
- Use `Array.prototype.filter()` to keep only those properties that are functions.
|
|
- Omit the second argument, `inherited`, to not include inherited properties by default.
|
|
|
|
```js
|
|
const functions = (obj, inherited = false) =>
|
|
(inherited
|
|
? [...Object.keys(obj), ...Object.keys(Object.getPrototypeOf(obj))]
|
|
: Object.keys(obj)
|
|
).filter(key => typeof obj[key] === 'function');
|
|
```
|
|
|
|
```js
|
|
function Foo() {
|
|
this.a = () => 1;
|
|
this.b = () => 2;
|
|
}
|
|
Foo.prototype.c = () => 3;
|
|
functions(new Foo()); // ['a', 'b']
|
|
functions(new Foo(), true); // ['a', 'b', 'c']
|
|
```
|