web:javascript:es:foreach

Table of Contents

About

forEach is a terminal javascript functional operation that will loop over each element:

on a array
or intermediaire functional programming method such as map

Example

The syntax is important, the function is called forEach with a uppercase E, otherwise you get a Unknown function call

Array

['blue', 'green', 'yellow'].forEach((color, index) => console.log(`${index} - ${color}`));

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Functional Programming

With map

['a','b','c']
    .map(letter => letter.toUpperCase())
    .forEach(letter => console.log(letter));

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Return and not continue

In a foreach loop, you should use the return function to stop the processing and not continue.