array

Estimated reading time: 9 minutes

Array

Array store a collections of values in a single variable . Array is actually a object.

Array represent by square brackets []

let users  = ['kamal','jamal','maruf']
console.log(users[1]);
// jamal

let users = new Array('kamal','jamal','maruf');
console.log(users[0]);
// kamal
name name name name name
from isArray of concat copyWithin
entries every fill filter find
findIndex flatMap flatten forEach includes
indexOf join keys lastIndexOf map
pop push reduce reduceRight reverse
shift slice some sort splice
toSource toString unShift values .

isArray

Array.isArray([1,2,3]);
// true

concat

let num = [2,4,5];
let con1 = [6,7,8];
let con2 = [9,10];

let resultConcat = num.concat(con1,con2);
console.log(resultConcat);
// [ 2, 4, 5, 6, 7, 8, 9, 10 ]

every()

  • check all elements
  • all satiesfied that time return true otherwise false
let users = ['kamal','jamal','maruf','sadia','karim'];
console.log(users.every(t => t != ''));
//  true
let users = ['kamal','jamal','maruf','sadia','karim'];
console.log(users.every(t => t == ''));
//  false

fill

  • fill(byValue,from_position,end_position)
  • start with 1 not 0
let users = ['kamal','jamal','maruf','sadia','karim'];
let afterFill = users.fill('rahim',1,4);
console.log(afterFill)
//  kamal,rahim,rahim,rahim,karim

filter

  • check then if fullfill any element that will be return
let users = ['kamal','jamal','maruf','sadia','karim'];
let afterFilter = users.filter(t => t.match('k'));
console.log(afterFilter)
//  kamal,karim

find

let users = ['kamal','jamal','maruf','sadia','karim'];
let afterFind = users.find(t => t.match('jamal'));
console.log(afterFind)

findIndex

let users = ['kamal','jamal','maruf','sadia','karim'];
let afterFindIndex = users.findIndex(t => t.match('karim'));
console.log(afterFindIndex)
//  4;

forEach

let users = ['kamal','jamal','maruf','sadia','karim'];
users.forEach(t => {
  console.log(t)
});

//  kamal,jamal,maruf,sadia,karim

includes

  • search exist or not
  • with position
  • include(searchElement,positionCheck)
let users = ['kamal','jamal','maruf','sadia','karim'];
let afterInclusers = users.includes('jamal',1);
console.log(afterInclusers);
//  true

indexOf

  • indexOf(element,afterIndex)
let users = ['kamal','jamal','maruf','sadia','karim','jamal'];
let result = users.indexOf('jamal');
console.log(result);
//  1
let users = ['kamal','jamal','maruf','sadia','karim','jamal'];
let result = users.indexOf('jamal',3);
console.log(result);
//  5

join

let users = ['kamal','jamal','maruf','sadia','karim','jamal'];
let result = users.join('-');
console.log(result);
//  kamal-jamal-maruf-sadia-karim-jamal

keys

let users = ['kamal','jamal','maruf','sadia','karim','jamal'];
let result = users.keys();
for (t of result) {
  console.log(t);
}

pop

  • delete last element
let users = ['kamal','maruf','jamal','sadia','karim'];
let result = users.pop();
console.log(users);
// pop: karim
// kamal,maruf,jamal,sadia

push

  • add new element at last position
let users = ['kamal','maruf','jamal','sadia','karim'];
 users.push('Human');
console.log(users);
 //["kamal", "maruf", "jamal", "sadia", "karim", "Human"]

reverse

let users = ['kamal','maruf','jamal','sadia','karim'];
 users.reverse()
console.log(users);
// ["karim", "sadia", "jamal", "maruf", "kamal"]

shift

  • delete 1st element
let users = ['kamal','maruf','jamal','sadia','karim'];
 users.shift()
console.log(users);
// [ "maruf", "jamal", "sadia", "karim"]

slice

  • slice(begin,end)
let users = ['kamal','maruf','jamal','sadia','karim'];
let result = users.slice(1,4);
console.log(result);
// ["maruf", "jamal", "sadia"]

some

  • any element fullfill the constion return turn
let users = ['kamal','maruf','jamal','','sadia','karim', ''];
let result = users.some(t => t == '');
console.log(result);
// true

sort

let users = ['kamal','maruf','jamal','sadia','karim'];
let result = users.sort()
console.log(users);
// ["jamal", "kamal", "karim", "maruf", "sadia"]

splice

  • increase element / constant element
  • set element a desired position
  • splice(position,howManyDelete,value)
let users = ['kamal','maruf','jamal','sadia','karim'];
let result = users.splice(1,0,'hasibur');
console.log(users);
// ["kamal", "hasibur", "maruf", "jamal", "sadia", "karim"]

let users = ['kamal','maruf','jamal','sadia','karim'];
let result = users.splice(1,1,'hasibur');
console.log(users);
// ["kamal", "hasibur", "jamal", "sadia", "karim"]

let users = ['kamal','maruf','jamal','sadia','karim'];
let result = users.splice(1,2,'hasibur','masud');
console.log(users);
// ["kamal", "hasibur", "masud", "sadia", "karim"]
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