8 Must Know JavaScript Array Methods

every.js

//return true if every item returns true 

let items = [
    { name: 'Bike',     price: 400 },
    { name: 'TV',       price: 1200 }
];

let cheapPrice = 1000;
let everyItemsHasCheapPrice = items.every((item) => {      
  return item.price <= cheapPrice     
});

everyItemsHasCheapPrice // false

filter.js

const filteredItems = items.filter((item) => {
    return item.price <= 100
});

find.js

return very first item in array

const foundItem = items.find((item) => {
    return item.name == "Antonio"
});

forEach.js

items.forEach((item) => {
    //here do something with item
    console.log(item.name)
});

includes.js

const items = [ 1 , 2, 3, 4, 5 ]
 
boolean includesTwo = items.includes(2)   // true
boolean includesTwo = items.includes(7)   // false

items array.js

const items = [
    { name: 'Bike',     price: 100 },
    { name: 'TV',       price: 200 },
    { name: 'Album',    price: 10 },
    { name: 'Book',     price: 5 },
    { name: 'Phone',    price: 500 },
    { name: 'Computer', price: 1000 },
    { name: 'Keyboard', price: 25 },
]

map.js

convert one array to another 

const itemNames = items.map((item) => {
    return item.name
});

reduce.js

reduce method do some operations on the array and returns the new array as result:

e.g. get total price of all items:

let initialValue = 0; 

const total = items.reduce((reducerVal, item) => {
  return item.price + reducerVal 
}, initialValue )

some .js

return true if at least one item returns true 
  
number cheapPrice = 100;

boolean hasSomeCheapItems = items.some((item) => {
  return item.price <= cheapPrice     
})

Source: https://youtu.be/R8rmfD9Y5-c