flatMap()

Use flatMap() creates a new array with sub-array elements flattened by specified depth.

example

[[2], [4], [6], [8]].flatMap(val => val/2) // [ 1, 2, 3, 4 ]

syntax

var new_array = arr.flatMap(function callback(currentValue[, index[, array]]) {
 // return element for new_array
}[, thisArg])

Getting the last element of a split string array

Remove array of objects from another array of objects

using Typescript callback style error handling

Rest Operator for Objects

Now we can use rest on the properties of an Object. It allows us to explicitly extract certain named variables, and assign any uncalled variables into a catchall Object.

10 mẹo sử dụng array và object trong javascript