andre/30-seconds-of-code
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Resolve #601

Browse Source 
Shorter and sweeter
This commit is contained in:
Angelos Chalaris
2018-03-06 20:58:53 +02:00
committed by GitHub
parent 1bba307091
commit 883063e278
1 changed files with 8 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
snippets/zipWith.md
View File

@ -2,22 +2,20 @@
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. 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.
Check if the last argument provided in a function. Check if the last argument provided is a function.
Use `Math.max()` to get the longest array in the arguments. Use `Math.max()` to get the longest array in the arguments.
Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements. Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements.
If lengths of the argument-arrays vary, `undefined` is used where no value could be found. If lengths of the argument-arrays vary, `undefined` is used where no value could be found.
The function is invoked with the elements of each group `(...group)`. The function is invoked with the elements of each group `(...group)`.
```js ```js
const zipWith = (...arrays) => { const zipWith = (...array) => {
const length = arrays.length; const fn = typeof array[array.length - 1] === 'function' ? array.pop() : undefined;
let fn = length > 1 ? arrays[length - 1] : undefined; return Array
fn = typeof fn == 'function' ? (arrays.pop(), fn) : undefined; .from(
const maxLength = Math.max(...arrays.map(x => x.length)); { length: Math.max(...array.map(a => a.length)) },
const result = Array.from({ length: maxLength }).map((_, i) => { (_, i) => (fn ? fn(...array.map(a => a[i])) : array.map(a => a[i])),
return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]); );
});
return fn ? result.map(arr => fn(...arr)) : result;
}; };
``` ```