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Tag: map-function

how to check a condition in object array [closed]

Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 3 months ago. Improve this question I am trying to use an array map for checking if same username and password exist in an object array Answer You may use find

Mapping Array in Javascript with sequential numbers

The following code: Creates the following Array: I just don’t understand why. I can’t find anything on the internet that explains this behavior. Does anyone know why this works the way it does? Perhaps a link to some documentation? Answer creates an array of length 10 with all elements being undefined. will invoke for each element with the arguments

What is the difference between .map, .every, and .forEach?

I’ve always wondered what the difference between them were. They all seem to do the same thing… Answer The difference is in the return values. .map() returns a new Array of objects created by taking some action on the original item. .every() returns a boolean – true if every element in this array satisfies the provided testing function. An important