9 lines
219 B
Markdown
9 lines
219 B
Markdown
### Flatten array
|
|
|
|
Use `Array.reduce()` to get all elements inside the array and `concat()` to flatten them.
|
|
|
|
```js
|
|
const flatten = arr => arr.reduce((a, v) => a.concat(v), []);
|
|
// flatten([1,[2],3,4]) -> [1,2,3,4]
|
|
```
|