add and remove element from array javascript code example

Example 1: remove an element from array

var colors = ["red", "blue", "car","green"];

// op1: with direct arrow function
colors = colors.filter(data => data != "car");

// op2: with function return value
colors = colors.filter(function(data) { return data != "car"});

Example 2: remove array js

var ar = [1, 2, 3, 4, 5, 6];ar.length = 4; // set length to remove elementsconsole.log( ar ); // [1, 2, 3, 4]
// //////////////////////////////////////
var ar = [1, 2, 3, 4, 5, 6];ar.pop(); // returns 6console.log( ar ); // [1, 2, 3, 4, 5]
// //////////////////////////////////////
var ar = ['zero', 'one', 'two', 'three'];ar.shift(); // returns "zero"console.log( ar ); // ["one", "two", "three"]
// //////////////////////////////////////
var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0];var removed = arr.splice(2,2);
// //////////////////////////////////////
["bar", "baz", "foo", "qux"]list.splice(0, 2) // Starting at index position 0, remove two elements ["bar", "baz"] and retains ["foo", "qux"].
// //////////////////////////////////////
var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
for( var i = 0; i < arr.length; i++){
  if ( arr[i] === 5) {
    arr.splice(i, 1); 
  }
}//=> [1, 2, 3, 4, 6, 7, 8, 9, 0]
// //////////////////////////////////////
var arr = [1, 2, 3, 4, 5, 5, 6, 7, 8, 5, 9, 0];
for( var i = 0; i < arr.length; i++){
  if ( arr[i] === 5) {
    arr.splice(i, 1); i--; 
  }
}//=> [1, 2, 3, 4, 6, 7, 8, 9, 0]
// //////////////////////////////////////
var array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
var filtered = array.filter(function(value, index, arr){
  return value > 5;
});//filtered => [6, 7, 8, 9]//array => [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
// //////////////////////////////////////
var evens = _.remove(array, function(n) {
  return n % 2 === 0;
});
console.log(array);// => [1, 3]console.log(evens);// => [2, 4]
// //////////////////////////////////////
function arrayRemove(arr, value) {
  return arr.filter(function(ele){
    return ele != value; });
}
var result = arrayRemove(array, 6);// result = [1, 2, 3, 4, 5, 7, 8, 9, 0]
// //////////////////////////////////////
var ar = [1, 2, 3, 4, 5, 6];delete ar[4]; // delete element with index 4console.log( ar ); // [1, 2, 3, 4, undefined, 6]alert( ar ); // 1,2,3,4,,6

Example 3: javascript function to add or remove from array if

function removeItemOnce(arr, value) {
  var index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  }
  return arr;
}

function removeItemAll(arr, value) {
  var i = 0;
  while (i < arr.length) {
    if (arr[i] === value) {
      arr.splice(i, 1);
    } else {
      ++i;
    }
  }
  return arr;
}
//Usage
console.log(removeItemOnce([2,5,9,1,5,8,5], 5))
console.log(removeItemAll([2,5,9,1,5,8,5], 5))