Array helpers for Javascript

I would like to represent you some useful Javascript helper functions for manipulating data.

.forEach()

forEach() calls a provided callback function once for each element in an array in ascending order.

Syntax:

arr.forEach(callback(currentValue[, index[, array]]) {
  // execute something
}[, thisArg]);

Example:

forEach() function

.filter()

flter() creates a new array with all elements that pass the test implemented by the provided function.

Syntax:

let newArray = arr.filter(callback(currentValue[, index[, array]]) {
  // return element for newArray, if true
}[, thisArg]);

Example:

filter() function

.find()

find() returns the value of the first element in the provided array that satisfies the provided condition.

Syntax:

arr.find(callback(element[, index[, array]])[, thisArg])

Example:

find() function

.map()

map() creates a new array with all elements that pass the test implemented by the provided function.

Syntax:

let newArray = arr.map(callback(currentValue[, index[, array]]) {
  // return element for newArray, after executing something
}[, thisArg]);

Example:

map() function

.reduce()

reduce() executes a reducer dunction (that you provide) on each element of the array, resulting in single output value.

Syntax:

arr.reduce(callback( accumulator, currentValue, [, index[, array]] )[, initialValue])

Example:

reduce() function