Array methods

Using splice to add items in any position

const arr = ['a','b','c','d']

x = arr.splice(2,0,'3')

x will be empty - []

arr will be ["a", "b", "3", "c", "d"]

Add to the beginning of array

arr.unshift(-13)

[-13, "a", "b", "3", "c", "d"]

remove 1^st item

arr.shift()

["a", "b", "3", "c", "d"]

For Each

var temp =””

arr.forEach(function (item) {

    if (isNaN(item)) {

        temp += item;

    }

});

temp = "abcd"

mapping

const test =[{name:"herby",cash:23},{name:"boris",cash:456} ]

const cash = test.map(x=>x.cash)

cash = [23, 456]

Every and Some

const test2 =[{name:"herby",cash:23,eyecolor:"brown"},{name:"boris",cash:456} ]

test2.some(x=>x.eyecolor)

true

test2.every(x=>x.eyecolor)

false

Find

returns 1^st item

const z = test2.find(x=>{return x.eyecolor === "brown"})

z    {name:"herby",cash:23,eyecolor:"brown"}

const w = test2.find(x=>{return x.cash  > 0})

w   {name:"herby",cash:23,eyecolor:"brown"}

to get multiple items as an array use:

Filter

const t = test2.filter(x=>{return x.cash  > 0})

sort

 ascending

test2.sort((x,z)=>x.cash -z.cash)

descending

test2.sort((x,z)=>z.cash -x.cash)

Aggregating

console.log(test2.reduce((a,c)=>a+=c.cash,0))

479