30 lines
1.1 KiB
Markdown
30 lines
1.1 KiB
Markdown
---
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title: shank
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tags: array,intermediate
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firstSeen: 2018-09-27T01:55:30+03:00
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lastUpdated: 2020-10-22T20:24:30+03:00
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---
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Has the same functionality as [`Array.prototype.splice()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice), but returning a new array instead of mutating the original array.
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- Use `Array.prototype.slice()` and `Array.prototype.concat()` to get an array with the new contents after removing existing elements and/or adding new elements.
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- Omit the second argument, `index`, to start at `0`.
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- Omit the third argument, `delCount`, to remove `0` elements.
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- Omit the fourth argument, `elements`, in order to not add any new elements.
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```js
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const shank = (arr, index = 0, delCount = 0, ...elements) =>
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arr
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.slice(0, index)
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.concat(elements)
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.concat(arr.slice(index + delCount));
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```
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```js
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const names = ['alpha', 'bravo', 'charlie'];
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const namesAndDelta = shank(names, 1, 0, 'delta');
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// [ 'alpha', 'delta', 'bravo', 'charlie' ]
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const namesNoBravo = shank(names, 1, 1); // [ 'alpha', 'charlie' ]
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console.log(names); // ['alpha', 'bravo', 'charlie']
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```
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