How to remove element from an array in Javascript?

First, I will give you answer using plain old Javascript to remove element in an array

To remove an element of an array at location(index) i:

arr.splice(i, 1); //remove 1 item at index 'i' of an array

To Remove every element (numberToremove) of specific type, you need to loop

function removeAllInstancesOfItem(arr, item) {
   for (var i = arr.length; i--;) {
     if (arr[i] === itemToRemove) 
        arr.splice(i, 1);
   }
}

It loops through the array backwards (as indexes and length will change when an item is removed) and removes the item if it's found.

Using JS ES6

let value = 4

let arr = [1, 2, 3, 4, 4, 5]

arr = arr.filter(item => item !== value)

console.log(arr);
// this will print [1,2,3,5]

But as ES6 is not supported in older browser like IE 10 or safari 10 version or below it, you would have to use BabelJS

Custom method to remove by value

You can also create custom method to remove item based on value, we will still use .splice() but it can be helpful

Array.prototype.removeByValue = function (val) {
  for (var i = 0; i < this.length; i++) {
    if (this[i] === val) {
      this.splice(i, 1);
      i--;
    }
  }
  return this;
}

var cars= ['bmw', 'audi', 'mercedes', 'jaguar'];
cars.removeByValue('audi');

console.log(cars); 
//[bmw', 'mercedes', 'jaguar']

Hope it helps.