reduce

Describing the reduce Operation

• The reduce operation is used for testing if every element of an array satisfies a condition

• It accepts a callback function with the following arguments:

  • accumulator: Accumulated value previously returned
  • currentValue: Current element processed in the array
  • index: Optional index of currentValue
  • array: Optional array that is called
  • thisArg: Optional value to use as this

Defining an Array

let fruits = ["Apple", "Banana"];
console.log(fruits.length);
// 2

Using the reduce Operation

// Regular function
fruits.reduce(function(accum, item) {
    return accum + item;
})
// "AppleBanana"

// Arrow function
fruits.reduce((accum, item) => accum + item);
// "AppleBanana"