8ee50178f3
Correct: `Array.from()` (it’s a static method) Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method) This patch uses the common `#` syntax to denote `.prototype.`.
17 lines
341 B
Markdown
17 lines
341 B
Markdown
### intersection
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Returns a list of elements that exist in both arrays.
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Create a `Set` from `b`, then use `Array.prototype.filter()` on `a` to only keep values contained in `b`.
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```js
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const intersection = (a, b) => {
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const s = new Set(b);
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return a.filter(x => s.has(x));
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};
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```
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```js
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intersection([1, 2, 3], [4, 3, 2]); // [2, 3]
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```
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