26 lines
783 B
Markdown
26 lines
783 B
Markdown
---
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title: Remove list elements until condition is met
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tags: array
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cover: blog_images/purple-sunset-beach.jpg
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firstSeen: 2020-11-29T12:04:53+02:00
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lastUpdated: 2020-11-29T12:04:53+02:00
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---
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Removes elements in an array until the passed function returns `true`.
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Returns the removed elements.
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- Loop through the array, using a `for...of` loop over `Array.prototype.entries()` until the returned value from the function is truthy.
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- Return the removed elements, using `Array.prototype.slice()`.
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- The callback function, `fn`, accepts a single argument which is the value of the element.
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```js
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const takeUntil = (arr, fn) => {
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for (const [i, val] of arr.entries()) if (fn(val)) return arr.slice(0, i);
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return arr;
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};
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```
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```js
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takeUntil([1, 2, 3, 4], n => n >= 3); // [1, 2]
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```
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