25 lines
826 B
Markdown
25 lines
826 B
Markdown
---
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title: isContainedIn
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tags: array,intermediate
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---
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Returns `true` if the elements of the first array are contained in the second one regardless of order, `false` otherwise.
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Use a `for...of` loop over a `Set` created from the first array.
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Use `Array.prototype.some()` to check if all distinct values are contained in the second array, use `Array.prototype.filter()` to compare the number of occurrences of each distinct value in both arrays.
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Return `false` if the count of any element is greater in the first array than the second one, `true` otherwise.
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```js
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const isContainedIn = (a, b) => {
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for (const v of new Set(a)) {
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if (!b.some(e => e === v) || a.filter(e => e === v).length > b.filter(e => e === v).length)
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return false;
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}
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return true;
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};
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```
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```js
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isContainedIn([1, 4], [2, 4, 1]); // true
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```
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