The map() method

The map() method loops through each element in array and calls the provided function for each element. This method creates a new array and doesn’t alter the original array.

const numbers = [5, 6, 8, 14, 32];

const updatedNumbers = numbers.map((number) => {
    return number + 10;
});

console.log(updatedNumbers); // [15, 16, 18, 24, 42]

The filter() method

The filter() method in JavaScript creates a new array with the elements that satisfies the provided condition. This method calls a provided function for each element in array and verifies the condition given in the provided function and passes only those elements that satisfy the given condition.

const numbers = [5, 6, 9, 32, 14];

const even = numbers.filter((number) => {
     return number % 2 === 0;
});

console.log(even); // [6, 32, 14]

The forEach() method

forEach() is used to execute the same code on every element in an array but does not change the array and it returns undefined.
Example:
In the example below we would use .forEach() to iterate over an array of food and log that we would want to eat each of them.

let food = ['mango','rice','pepper','pear'];

food.forEach(function(foodItem){ 

console.log('I want to eat '+foodItem);
});

Hope you have got a clear idea about both JavaScript array methods map() filter() and forEach().