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How do I remove a specific value from an array? Something like:

array.remove(value);

Constraints: I have to use core JavaScript. Frameworks are not allowed.

How do I remove a specific value from an array? Something like:

array.remove(value);

Constraints: I have to use core JavaScript. Frameworks are not allowed.

• javascript
• arrays

Share Improve this question Follow edited Feb 6, 2023 at 14:23 Muhammad Asad 3,79311 gold badge2424 silver badges3838 bronze badges asked Apr 23, 2011 at 22:17 WalkerWalker 134k2929 gold badges6969 silver badges9797 bronze badges 3

• In modern JavaScript (ES6) you can use Sets which have a in-built Set.delete(elmnt) method – Krokodil Commented Nov 2, 2023 at 22:32
• @GustavoGonçalves yes. arrays should have a remove method and if anyone says "what about if the developer added it already?" then make it a weak add. If the remove member/function does not exist on the array then add it. Array needs it. – 1.21 gigawatts Commented Dec 6, 2023 at 2:57
• 5 @1.21gigawatts that doesn't work because the custom remove method can have different signature or semantics from one added later. Therefore arr.remove(foo) can start to behave differently if it's later added to arrays and your custom method addition yields to that implementation. And that's not even a hypothetical, it's something that happens with MooTools and Array#contains. This literally had an effect of the whole of the internet because contains was removed to includes to avoid that clash. – VLAZ Commented Dec 6, 2023 at 6:36

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50 Answers 50

Sorted by: Reset to default 1 2 Next 16856

Find the index of the array element you want to remove using indexOf, and then remove that index with splice.

The splice() method changes the contents of an array by removing existing elements and/or adding new elements.

const array = [2, 5, 9];

console.log(array);

const index = array.indexOf(5);
if (index > -1) { // only splice array when item is found
  array.splice(index, 1); // 2nd parameter means remove one item only
}

// array = [2, 9]
console.log(array);

The second parameter of splice is the number of elements to remove. Note that splice modifies the array in place and returns a new array containing the elements that have been removed.

---

For completeness, here are functions. The first function removes only a single occurrence (e.g., removing the first match of 5 from [2,5,9,1,5,8,5]), while the second function removes all occurrences:

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))

In TypeScript, these functions can stay type-safe with a type parameter:

function removeItem<T>(arr: Array<T>, value: T): Array<T> {
  const index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  }
  return arr;
}

• Do it simple, intuitive and explicit (Occam's razor)
• Do it immutable (original array stays unchanged)
• Do it with standard JavaScript functions, if your browser doesn't support them - use polyfill

In this code example I use array.filter(...) function to remove unwanted items from an array. This function doesn't change the original array and creates a new one. If your browser doesn't support this function (e.g. Internet Explorer before version 9, or Firefox before version 1.5), consider polyfilling with core-js.

Be mindful though, creating a new array every time takes a big performance hit. If the list is very large (think 10k+ items) then consider using other methods.

Removing item (ECMA-262 Edition 5 code AKA old style JavaScript)

var value = 3

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

arr = arr.filter(function(item) {
    return item !== value
})

console.log(arr)
// [ 1, 2, 4, 5 ]

Removing item (ECMAScript 6 code)

let value = 3

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

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

console.log(arr)
// [ 1, 2, 4, 5 ]

IMPORTANT ECMAScript 6 () => {} arrow function syntax is not supported in Internet Explorer at all, Chrome before version 45, Firefox before version 22, and Safari before version 10. To use ECMAScript 6 syntax in old browsers you can use BabelJS.

---

Removing multiple items (ECMAScript 7 code)

An additional advantage of this method is that you can remove multiple items

let forDeletion = [2, 3, 5]

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

arr = arr.filter(item => !forDeletion.includes(item))
// !!! Read below about array.includes(...) support !!!

console.log(arr)
// [ 1, 4 ]

IMPORTANT array.includes(...) function is not supported in Internet Explorer at all, Chrome before version 47, Firefox before version 43, Safari before version 9, and Edge before version 14 but you can polyfill with core-js.

Removing multiple items (in the future, maybe)

If the "This-Binding Syntax" proposal is ever accepted, you'll be able to do this:

// array-lib.js

export function remove(...forDeletion) {
    return this.filter(item => !forDeletion.includes(item))
}

// main.js

import { remove } from './array-lib.js'

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

// :: This-Binding Syntax Proposal
// using "remove" function as "virtual method"
// without extending Array.prototype
arr = arr::remove(2, 3, 5)

console.log(arr)
// [ 1, 4 ]

Try it yourself in BabelJS :)

Reference

• Array.prototype.includes
• Functional composition

I don't know how you are expecting array.remove(int) to behave. There are three possibilities I can think of that you might be wanting.

To remove an element of an array at an index i:

array.splice(i, 1);

If you want to remove every element with value number from the array:

for(var i = array.length - 1; i >= 0; i--) {
    if(array[i] === number) {
       array.splice(i, 1);
    }
}

If you just want to make the element at index i no longer exist, but you don't want the indexes of the other elements to change:

delete array[i];

It depends on whether you want to keep an empty spot or not.

If you do want an empty slot:

array[index] = undefined;

If you don't want an empty slot:

// To keep the original:
// oldArray = [...array];

// This modifies the array.
array.splice(index, 1);

And if you need the value of that item, you can just store the returned array's element:

var value = array.splice(index, 1)[0];

If you want to remove at either end of the array, you can use array.pop() for the last one or array.shift() for the first one (both return the value of the item as well).

If you don't know the index of the item, you can use array.indexOf(item) to get it (in a if() to get one item or in a while() to get all of them). array.indexOf(item) returns either the index or -1 if not found. 

There are two major approaches

1. splice(): anArray.splice(index, 1);

   let fruits = ['Apple', 'Banana', 'Mango', 'Orange']
   let removed = fruits.splice(2, 1);
   // fruits is ['Apple', 'Banana', 'Orange']
   // removed is ['Mango']
   

2. delete: delete anArray[index];

   let fruits = ['Apple', 'Banana', 'Mango', 'Orange']
   let removed = delete fruits(2);
   // fruits is ['Apple', 'Banana', undefined, 'Orange']
   // removed is true
   

Be careful when you use the delete for an array. It is good for deleting attributes of objects, but not so good for arrays. It is better to use splice for arrays.

Keep in mind that when you use delete for an array you could get wrong results for anArray.length. In other words, delete would remove the element, but it wouldn't update the value of the length property.

You can also expect to have holes in index numbers after using delete, e.g. you could end up with having indexes 1, 3, 4, 8, 9, and 11 and length as it was before using delete. In that case, all indexed for loops would crash, since indexes are no longer sequential.

If you are forced to use delete for some reason, then you should use for each loops when you need to loop through arrays. As the matter of fact, always avoid using indexed for loops, if possible. That way the code would be more robust and less prone to problems with indexes.

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 fruits = ['apple', 'banana', 'carrot', 'orange'];
fruits.removeByValue('banana');

console.log(fruits);
// -> ['apple', 'carrot', 'orange']

There isn't any need to use indexOf or splice. However, it performs better if you only want to remove one occurrence of an element.

Find and move (move):

function move(arr, val) {
  var j = 0;
  for (var i = 0, l = arr.length; i < l; i++) {
    if (arr[i] !== val) {
      arr[j++] = arr[i];
    }
  }
  arr.length = j;
}

Use indexOf and splice (indexof):

function indexof(arr, val) {
  var i;
  while ((i = arr.indexOf(val)) != -1) {
    arr.splice(i, 1);
  }
}

Use only splice (splice):

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

Run-times on Node.js for an array with 1000 elements (averaged over 10,000 runs):

indexof is approximately 10 times slower than move. Even if improved by removing the call to indexOf in splice, it performs much worse than move.

Remove all occurrences:
    move 0.0048 ms
    indexof 0.0463 ms
    splice 0.0359 ms

Remove first occurrence:
    move_one 0.0041 ms
    indexof_one 0.0021 ms

This provides a predicate instead of a value.

NOTE: it will update the given array, and return the affected rows.

Usage

var removed = helper.remove(arr, row => row.id === 5 );

var removed = helper.removeAll(arr, row => row.name.startsWith('BMW'));

Definition

var helper = {
 // Remove and return the first occurrence

 remove: function(array, predicate) {
  for (var i = 0; i < array.length; i++) {
   if (predicate(array[i])) {
    return array.splice(i, 1);
   }
  }
 },

 // Remove and return all occurrences

 removeAll: function(array, predicate) {
  var removed = [];

  for (var i = 0; i < array.length; ) {
   if (predicate(array[i])) {
    removed.push(array.splice(i, 1));
    continue;
   }
   i++;
  }
  return removed;
 },
};

You can do it easily with the filter method:

function remove(arrOriginal, elementToRemove){
    return arrOriginal.filter(function(el){return el !== elementToRemove});
}
console.log(remove([1, 2, 1, 0, 3, 1, 4], 1));

This removes all elements from the array and also works faster than a combination of slice and indexOf.

John Resig posted a good implementation:

// Array Remove - By John Resig (MIT Licensed)
Array.prototype.remove = function(from, to) {
  var rest = this.slice((to || from) + 1 || this.length);
  this.length = from < 0 ? this.length + from : from;
  return this.push.apply(this, rest);
};

If you don’t want to extend a global object, you can do something like the following, instead:

// Array Remove - By John Resig (MIT Licensed)
Array.remove = function(array, from, to) {
    var rest = array.slice((to || from) + 1 || array.length);
    array.length = from < 0 ? array.length + from : from;
    return array.push.apply(array, rest);
};

But the main reason I am posting this is to warn users against the alternative implementation suggested in the comments on that page (Dec 14, 2007):

Array.prototype.remove = function(from, to) {
  this.splice(from, (to=[0, from || 1, ++to - from][arguments.length]) < 0 ? this.length + to : to);
  return this.length;
};

It seems to work well at first, but through a painful process I discovered it fails when trying to remove the second to last element in an array. For example, if you have a 10-element array and you try to remove the 9th element with this:

myArray.remove(8);

You end up with an 8-element array. I don't know why, but I confirmed John's original implementation doesn't have this problem.

Underscore.js can be used to solve issues with multiple browsers. It uses in-build browser methods if present. If they are absent like in the case of older Internet Explorer versions it uses its own custom methods.

A simple example to remove elements from array (from the website):

_.without([1, 2, 1, 0, 3, 1, 4], 0, 1); // => [2, 3, 4]

If you want a new array with the deleted positions removed, you can always delete the specific element and filter out the array. It might need an extension of the array object for browsers that don't implement the filter method, but in the long term it's easier since all you do is this:

var my_array = [1, 2, 3, 4, 5, 6];
delete my_array[4];
console.log(my_array.filter(function(a) {
  return typeof a !== 'undefined';
}));

It should display [1, 2, 3, 4, 6].

Check out this code. It works in every major browser.

remove_item = function(arr, value) {
  var b = '';
  for (b in arr) {
    if (arr[b] === value) {
      arr.splice(b, 1);
      break;
    }
  }
  return arr;
};

var array = [1,3,5,6,5,9,5,3,55];
var res = remove_item(array,5);
console.log(res);

You can use lodash _.pull (mutate array), _.pullAt (mutate array) or _.without (does't mutate array),

var array1 = ['a', 'b', 'c', 'd']
_.pull(array1, 'c')
console.log(array1) // ['a', 'b', 'd']

var array2 = ['e', 'f', 'g', 'h']
_.pullAt(array2, 0)
console.log(array2) // ['f', 'g', 'h']

var array3 = ['i', 'j', 'k', 'l']
var newArray = _.without(array3, 'i') // ['j', 'k', 'l']
console.log(array3) // ['i', 'j', 'k', 'l']

ES6 & without mutation: (October 2016)

const removeByIndex = (list, index) => [
  ...list.slice(0, index),
  ...list.slice(index + 1)
];
         
output = removeByIndex([33, 22, 11, 44], 1); // -> [33, 11, 44]
      
console.log(output);

Performance

Today (2019-12-09) I conduct performance tests on macOS v10.13.6 (High Sierra) for chosen solutions. I show delete (A), but I do not use it in comparison with other methods, because it left empty space in the array.

The conclusions

• the fastest solution is array.splice (C) (except Safari for small arrays where it has the second time)
• for big arrays, array.slice+splice (H) is the fastest immutable solution for Firefox and Safari; Array.from (B) is fastest in Chrome
• mutable solutions are usually 1.5x-6x faster than immutable
• for small tables on Safari, surprisingly the mutable solution (C) is slower than the immutable solution (G)

Details

In tests, I remove the middle element from the array in different ways. The A, C solutions are in-place. The B, D, E, F, G, H solutions are immutable.

Results for an array with 10 elements

In Chrome the array.splice (C) is the fastest in-place solution. The array.filter (D) is the fastest immutable solution. The slowest is array.slice (F). You can perform the test on your machine here.

Results for an array with 1.000.000 elements

In Chrome the array.splice (C) is the fastest in-place solution (the delete (C) is similar fast - but it left an empty slot in the array (so it does not perform a 'full remove')). The array.slice-splice (H) is the fastest immutable solution. The slowest is array.filter (D and E). You can perform the test on your machine here.

var a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
var log = (letter,array) => console.log(letter, array.join `,`);

function A(array) {
  var index = array.indexOf(5);
  delete array[index];
  log('A', array);
}

function B(array) {
  var index = array.indexOf(5);
  var arr = Array.from(array);
  arr.splice(index, 1)
  log('B', arr);
}

function C(array) {
  var index = array.indexOf(5);
  array.splice(index, 1);
  log('C', array);
}

function D(array) {
  var arr = array.filter(item => item !== 5)
  log('D', arr);
}

function E(array) {
  var index = array.indexOf(5);
  var arr = array.filter((item, i) => i !== index)
  log('E', arr);
}

function F(array) {
  var index = array.indexOf(5);
  var arr = array.slice(0, index).concat(array.slice(index + 1))
  log('F', arr);
}

function G(array) {
  var index = array.indexOf(5);
  var arr = [...array.slice(0, index), ...array.slice(index + 1)]
  log('G', arr);
}

function H(array) {
  var index = array.indexOf(5);
  var arr = array.slice(0);
  arr.splice(index, 1);
  log('H', arr);
}

A([...a]);
B([...a]);
C([...a]);
D([...a]);
E([...a]);
F([...a]);
G([...a]);
H([...a]);

This snippet only presents code used in performance tests - it does not perform tests itself.

Comparison for browsers: Chrome v78.0.0, Safari v13.0.4, and Firefox v71.0.0

OK, for example you have the array below:

var num = [1, 2, 3, 4, 5];

And we want to delete number 4. You can simply use the below code:

num.splice(num.indexOf(4), 1); // num will be [1, 2, 3, 5];

If you are reusing this function, you write a reusable function which will be attached to the native array function like below:

Array.prototype.remove = Array.prototype.remove || function(x) {
  const i = this.indexOf(x);
  if(i===-1)
      return;
  this.splice(i, 1); // num.remove(5) === [1, 2, 3];
}

But how about if you have the below array instead with a few [5]s in the array?

var num = [5, 6, 5, 4, 5, 1, 5];

We need a loop to check them all, but an easier and more efficient way is using built-in JavaScript functions, so we write a function which use a filter like below instead:

const _removeValue = (arr, x) => arr.filter(n => n!==x);
//_removeValue([1, 2, 3, 4, 5, 5, 6, 5], 5) // Return [1, 2, 3, 4, 6]

Also there are third-party libraries which do help you to do this, like Lodash or Underscore. For more information, look at lodash _.pull, _.pullAt or _.without.

I'm pretty new to JavaScript and needed this functionality. I merely wrote this:

function removeFromArray(array, item, index) {
  while((index = array.indexOf(item)) > -1) {
    array.splice(index, 1);
  }
}

Then when I want to use it:

// Set-up some dummy data
var dummyObj = { name: "meow" };
var dummyArray = [dummyObj, "item1", "item1", "item2"];

// Remove the dummy data
removeFromArray(dummyArray, dummyObj);
removeFromArray(dummyArray, "item2");

Output - As expected: ["item1", "item1"]

You may have different needs than I, so you can easily modify it to suit them. I hope this helps someone.

You should never mutate your array as this is against the functional programming pattern. You can create a new array without referencing the one you want to change data of using the ECMAScript 6 method filter;

var myArray = [1, 2, 3, 4, 5, 6];

Suppose you want to remove 5 from the array, you can simply do it like this:

myArray = myArray.filter(value => value !== 5);

This will give you a new array without the value you wanted to remove. So the result will be:

 [1, 2, 3, 4, 6]; // 5 has been removed from this array

For further understanding you can read the MDN documentation on Array.filter.

A more modern, ECMAScript 2015 (formerly known as Harmony or ES 6) approach. Given:

const items = [1, 2, 3, 4];
const index = 2;

Then:

items.filter((x, i) => i !== index);

Yielding:

[1, 2, 4]

You can use Babel and a polyfill service to ensure this is well supported across browsers.

Array.prototype.removeItem = function(a) {
    for (i = 0; i < this.length; i++) {
        if (this[i] == a) {
            for (i2 = i; i2 < this.length - 1; i2++) {
                this[i2] = this[i2 + 1];
            }
            this.length = this.length - 1
            return;
        }
    }
}

var recentMovies = ['Iron Man', 'Batman', 'Superman', 'Spiderman'];
recentMovies.removeItem('Superman');

2021 UPDATE

Your question is about how to remove a specific item from an array. By specific item you are referring to a number eg. remove number 5 from array. From what I understand you are looking for something like:

// PSEUDOCODE, SCROLL FOR COPY-PASTE CODE
[1,2,3,4,5,6,8,5].remove(5) // result: [1,2,3,4,6,8]

As for 2021 the best way to achieve it is to use array filter function:

const input = [1,2,3,4,5,6,8,5];
const removeNumber = 5;
const result = input.filter(
    item => item != removeNumber
);

The above example uses array.prototype.filter function. It iterates over all array items, and returns only those satisfying the arrow function. As a result, the old array stays intact, while a new array called result contains all items that are not equal to five. You can test it yourself online.

You can visualize array.prototype.filter like this:

Considerations

Code quality

Array.prototype.filter is far the most readable method to remove a number in this case. It leaves little place for mistakes and uses core JS functionality.

Why not array.prototype.map?

Array.prototype.map is sometimes considered as an alternative for array.prototype.filter for that use case. But it should not be used. The reason is that array.prototype.filter is conceptually used to filter items that satisfy an arrow function (exactly what we need), while array.prototype.map is used to transform items. Since we don't change items while iterating over them, the proper function to use is array.prototype.filter.

Support

As of today (11.4.2022) 94,08% of Internet users' browsers support array.prototype.filter. So generally speaking it is safe to use. However, IE6 - 8 does not support it. So if your use case requires support for these browsers there is a nice polyfill made by Chris Ferdinanti.

Performance

Array.prototype.filter is great for most use cases. However if you are looking for some performance improvements for advanced data processing you can explore some other options like using pure for. Another great option is to rethink if the array you are processing really has to be so big. It may be a sign that the JavaScript should receive a reduced array for processing from the data source.

A benchmark of the different possibilities: https://jsben.ch/C5MXz

I tested splice and filter to see which is faster:

let someArr = [...Array(99999).keys()] 

console.time('filter')
someArr.filter(x => x !== 6666)
console.timeEnd('filter')

console.time('splice by indexOf')
someArr.splice(someArr.indexOf(6666), 1)
console.timeEnd('splice by indexOf')

On my machine, splice is faster. This makes sense, as splice merely edits an existing array, whereas filter creates a new array.

That said, filter is logically cleaner (easier to read) and fits better into a coding style that uses immutable state. So it's up to you whether you want to make that trade-off.

EDIT:

To be clear, splice and filter do different things: splice edits an array, whereas filter creates a new one. But either can be used to obtain an array with a given element removed.

I like this one-liner:

arr.includes(val) && arr.splice(arr.indexOf(val), 1)

• Only removes one value at a time.
• Support removing values such as null or undefined or object references - but not NaN (indexOf doesn't support NaN).
• Fast for large arrays (>million): includes+indexOf+splice combined are ~10x faster than filter or for.

As a prototype

// remove by value. return true if value found and removed, false otherwise
Array.prototype.removeByValue = function(val)
{
    return this.includes(val) && !!this.splice(this.indexOf(val), 1);
}

(Yes, I read all other answers and couldn't find one that combines includes and splice in the same line.)

I also ran into the situation where I had to remove an element from Array. .indexOf was not working in Internet Explorer, so I am sharing my working jQuery.inArray() solution:

var index = jQuery.inArray(val, arr);
if (index > -1) {
    arr.splice(index, 1);
    //console.log(arr);
}

You can iterate over each array-item and splice it if it exists in your array.

function destroy(arr, val) {
    for (var i = 0; i < arr.length; i++) if (arr[i] === val) arr.splice(i, 1);
    return arr;
}

I think many of the JavaScript instructions are not well thought out for functional programming. Splice returns the deleted element where most of the time you need the reduced array. This is bad.

Imagine you are doing a recursive call and have to pass an array with one less item, probably without the current indexed item. Or imagine you are doing another recursive call and has to pass an array with an element pushed.

In neither of these cases you can do myRecursiveFunction(myArr.push(c)) or myRecursiveFunction(myArr.splice(i,1)). The first idiot will in fact pass the length of the array and the second idiot will pass the deleted element as a parameter.

So what I do in fact... For deleting an array element and passing the resulting to a function as a parameter at the same time I do as follows

myRecursiveFunction(myArr.slice(0,i).concat(a.slice(i+1)))

When it comes to push that's more silly... I do like,

myRecursiveFunction((myArr.push(c),myArr))

I believe in a proper functional language a method mutating the object it's called upon must return a reference to the very object as a result.

2017-05-08

Most of the given answers work for strict comparison, meaning that both objects reference the exact same object in memory (or are primitive types), but often you want to remove a non-primitive object from an array that has a certain value. For instance, if you make a call to a server and want to check a retrieved object against a local object.

const a = {'field': 2} // Non-primitive object
const b = {'field': 2} // Non-primitive object with same value
const c = a            // Non-primitive object that reference the same object as "a"

assert(a !== b) // Don't reference the same item, but have same value
assert(a === c) // Do reference the same item, and have same value (naturally)

//Note: there are many alternative implementations for valuesAreEqual
function valuesAreEqual (x, y) {
   return  JSON.stringify(x) === JSON.stringify(y)
}


//filter will delete false values
//Thus, we want to return "false" if the item
// we want to delete is equal to the item in the array
function removeFromArray(arr, toDelete){
    return arr.filter(target => {return !valuesAreEqual(toDelete, target)})
}

const exampleArray = [a, b, b, c, a, {'field': 2}, {'field': 90}];
const resultArray = removeFromArray(exampleArray, a);

//resultArray = [{'field':90}]

There are alternative/faster implementations for valuesAreEqual, but this does the job. You can also use a custom comparator if you have a specific field to check (for example, some retrieved UUID vs a local UUID).

Also note that this is a functional operation, meaning that it does not mutate the original array.

In ES6, the Set collection provides a delete method to delete a specific value from the array, then convert the Set collection to an array by spread operator.

function deleteItem(list, val) {
    const set = new Set(list);
    set.delete(val);
    
    return [...set];
}

const letters = ['A', 'B', 'C', 'D', 'E'];
console.log(deleteItem(letters, 'C')); // ['A', 'B', 'D', 'E']

What a shame you have an array of integers, not an object where the keys are string equivalents of these integers.

I've looked through a lot of these answers and they all seem to use "brute force" as far as I can see. I haven't examined every single one, apologies if this is not so. For a smallish array this is fine, but what if you have 000s of integers in it?

Correct me if I'm wrong, but can't we assume that in a key => value map, of the kind which a JavaScript object is, that the key retrieval mechanism can be assumed to be highly engineered and optimised? (NB: if some super-expert tells me that this is not the case, I can suggest using ECMAScript 6's Map class instead, which certainly will be).

I'm just suggesting that, in certain circumstances, the best solution might be to convert your array to an object... the problem being, of course, that you might have repeating integer values. I suggest putting those in buckets as the "value" part of the key => value entries. (NB: if you are sure you don't have any repeating array elements this can be much simpler: values "same as" keys, and just go Object.values(...) to get back your modified array).

So you could do:

const arr = [ 1, 2, 55, 3, 2, 4, 55 ];
const f =    function( acc, val, currIndex ){
    // We have not seen this value before: make a bucket... NB: although val's typeof is 'number',
    // there is seamless equivalence between the object key (always string)
    // and this variable val.
    ! ( val in acc ) ? acc[ val ] = []: 0;
    // Drop another array index in the bucket
    acc[ val ].push( currIndex );
    return acc;
}
const myIntsMapObj = arr.reduce( f, {});

console.log( myIntsMapObj );

Output:

Object [ <1 empty slot>, Array1, Array[2], Array1, Array1, <5 empty slots>, 46 more… ]

It is then easy to delete all the numbers 55.

delete myIntsMapObj[ 55 ]; // Again, although keys are strings this works

You don't have to delete them all: index values are pushed into their buckets in order of appearance, so (for example):

myIntsMapObj[ 55 ].shift(); // And
myIntsMapObj[ 55 ].pop();

will delete the first and last occurrence respectively. You can count frequency of occurrence easily, replace all 55s with 3s by transferring the contents of one bucket to another, etc.

Retrieving a modified int array from your "bucket object" is slightly involved but not so much: each bucket contains the index (in the original array) of the value represented by the (string) key. Each of these bucket values is also unique (each is the unique index value in the original array): so you turn them into keys in a new object, with the (real) integer from the "integer string key" as value... then sort the keys and go Object.values( ... ).

This sounds very involved and time-consuming... but obviously everything depends on the circumstances and desired usage. My understanding is that all versions and contexts of JavaScript operate only in one thread, and the thread doesn't "let go", so there could be some horrible congestion with a "brute force" method: caused not so much by the indexOf ops, but multiple repeated slice/splice ops.

Addendum If you're sure this is too much engineering for your use case surely the simplest "brute force" approach is

const arr = [ 1, 2, 3, 66, 8, 2, 3, 2 ];
const newArray = arr.filter( number => number !== 3 );
console.log( newArray )

(Yes, other answers have spotted Array.prototype.filter...)

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