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Update README.md

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use Array.from instead of Array.apply
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panshao
2017-12-14 14:09:46 +08:00
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parent 7ffd624004
commit e421b1d49d
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README.md
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@ -185,14 +185,14 @@ const palindrome = str => {
### Chunk array
Use `Array.apply()` to create a new array, that fits the number of chunks that will be produced.
Use `Array.map()` to map each element of the new array to a chunk the length of `size`.
Use `Array.from(arrayLike[, mapFn[, thisArg]])` to create a new array, that fits the number of chunks that will be produced.
Use `mapFn` to map each element of the new array to a chunk the length of `size`.
If the original array can't be split evenly, the final chunk will contain the remaining elements.
```js
const chunk = (arr, size) =>
Array.apply(null, {length: Math.ceil(arr.length / size)}).map((v, i) => arr.slice(i * size, i * size + size));
// chunk([1,2,3,4,5], 2) -> [[1,2],[3,4],5]
Array.from({length: Math.ceil(arr.length / size)}, (v, i) => arr.slice(i * size, i * size + size));
// chunk([1,2,3,4,5], 2) -> [[1,2],[3,4],5]
```
### Count occurrences of a value in array