32 lines
1.1 KiB
Markdown
32 lines
1.1 KiB
Markdown
---
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title: zipWith
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tags: array,function,advanced
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---
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Creates an array of elements, grouped based on the position in the original arrays and using function as the last value to specify how grouped values should be combined.
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Check if the last argument provided is a function.
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Use `Math.max()` to get the longest array in the arguments.
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Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements.
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If lengths of the argument-arrays vary, `undefined` is used where no value could be found.
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The function is invoked with the elements of each group `(...group)`.
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```js
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const zipWith = (...array) => {
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const fn = typeof array[array.length - 1] === 'function' ? array.pop() : undefined;
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return Array.from(
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{ length: Math.max(...array.map(a => a.length)) },
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(_, i) => (fn ? fn(...array.map(a => a[i])) : array.map(a => a[i]))
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);
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};
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```
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```js
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zipWith([1, 2], [10, 20], [100, 200], (a, b, c) => a + b + c); // [111,222]
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zipWith(
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[1, 2, 3],
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[10, 20],
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[100, 200],
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(a, b, c) => (a != null ? a : 'a') + (b != null ? b : 'b') + (c != null ? c : 'c')
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); // [111, 222, '3bc']
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``` |