Today I Learned - Rocky Kev

TIL use JS filter like a pro

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TAGS: javascript arrays

To remove falsy items, we use .filter() (Array.prototype.filter()), which returns a new array containing just the array items for which the function passed in to .filter() evaluated to true.

You can use the Boolean constructor (Boolean()) to “coerce” a value to either true or false, which are the Boolean primitive types.

The question:

Explain why you can abbreviate .filter(item=>Boolean(item)) to .filter(Boolean).
The first argument to .filter() is a callback function, so you can pass in any existing function instead of making a new one.

In this case, Boolean and (item)=>Boolean(item) are the same callback function. (You can always try it in the console to be sure.)

Via this medium post - which is locked
(Kent C. Dodds’ .filter() Trick Will Change How You Use JavaScript)[https://medium.com/coding-at-dawn/kent-c-dodds-filter-trick-will-change-how-you-use-javascript-87b5112f9f6d]

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