20 lines
633 B
Markdown
20 lines
633 B
Markdown
---
|
|
title: differenceWith
|
|
tags: array,intermediate
|
|
---
|
|
|
|
Filters out all values from an array for which the comparator function does not return `true`.
|
|
|
|
- Use `Array.prototype.filter()` and `Array.prototype.findIndex()` to find the appropriate values.
|
|
- Omit the last argument, `comp`, to use a default strict equality comparator.
|
|
|
|
```js
|
|
const differenceWith = (arr, val, comp = (a, b) => a === b) =>
|
|
arr.filter(a => val.findIndex(b => comp(a, b)) === -1);
|
|
```
|
|
|
|
```js
|
|
differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2]
|
|
differenceWith([1, 1.2, 1.3], [1, 1.3, 1.5]); // [1.2]
|
|
```
|