Functional Array Manipulation

functional-array-manipulation.js

// Return a new array minus a given item
var a = [1, 2, 3, 4, 5]
var b = a.filter(item => item !== 2) // [1, 3, 4, 5]

// Return true if a value is in an array
var a = [1, 2, 3, 4, 5]
var b = a.some(item => item === 1) // true
var b = a.some(item => item === 6) // false

// Return the full item if a value is in an array
var a = [1, 2, 3, 4, 5]
var b = a.find(item => item === 1) // 1
var b = a.find(item => item === 6) // undefined

// Transform array of objects into a new array of new values
var a = [{ id: '1'}, { id: '2'}, { id: '3'}]
var b = a.reduce((arr, item) => arr.concat(item.id), []) // ['1', '2', '3']