Array forEach()

Use Array forEach() to iterate over the array items and call the function for each item.

Syntax

array.forEach(function callback(arrayItem, index, array), thisValue);

array - The array to iterate over.

Arguments

arrayItem

Next array item to be processed by the function.

index

Index of the current arrayItem being processed.

array

The array being iterated over.

thisValue

Item to represent the this value.

Return Value

This function always returns undefined.

Notes

• The array is not mutated.
• Adding items to the array after iterations have begun, will not be included in the processing.
• Changing the array items during processing will not change the item value passed into the function; the original value is used.
• forEach() cannot be chained.

Example

const letters = ['a', 'b', 'c'];

letters.forEach((letter, index, arr) => {
  console.log(letter, index, arr);
});

// The console will output
// 'a', 0, ['a', 'b', 'c']
// 'b', 1, ['a', 'b', 'c']
// 'c', 2, ['a', 'b', 'c']