How do I remove an array item in TypeScript?

I have an array that I've created in TypeScript and it has a property that I use as a key. If I have that key, how can I remove an item from it?

18 Answers

Same way as you would in JavaScript.

delete myArray[key]; 

Note that this sets the element to undefined.

Better to use the Array.prototype.splice function:

const index = myArray.indexOf(key, 0); if (index > -1) { myArray.splice(index, 1); } 

let foo_object; // Itemitem(object here) to remove this.foo_objects = this.foo_objects.filter(obj => return obj !== foo_object); 

With ES6 you can use this code :

removeDocument(doc){ this.documents.forEach( (item, index) => { if(item === doc) this.documents.splice(index,1); }); } 

It is my solution for that:

onDelete(id: number) { this.service.delete(id).then(() => { let index = this.documents.findIndex(d => d.id === id); //find index in your array this.documents.splice(index, 1);//remove element from array }); event.stopPropagation(); } 

You can use the splice method on an array to remove the elements.

for example if you have an array with the name arr use the following:

arr.splice(2, 1); 

so here the element with index 2 will be the starting point and the argument 2 will determine how many elements to be deleted.

If you want to delete the last element of the array named arr then do this:

arr.splice(arr.length-1, 1); 

This will return arr with the last element deleted.

Example:

var arr = ["orange", "mango", "banana", "sugar", "tea"]; arr.splice(arr.length-1, 1) console.log(arr); // return ["orange", "mango", "banana", "sugar"] 

let departments is an array. You want to remove an item from this array.

departments: string[] = []; removeDepartment(name: string): void { this.departments = this.departments.filter(item => item != name); } 

This worked for me.

Your array:

DummyArray: any = [ { "id": 1, "name": 'A' }, { "id": 2, "name": 'B' }, { "id": 3, "name": 'C' }, { "id": 4, "name": 'D' } ] 

Function:

remove() { this.DummyArray = this.DummyArray.filter(item => item !== item); } 

Note: This function deletes all the objects form your array. If you want to delete a specific object from array then use this method:

remove(id) { this.DummyArray = this.DummyArray.filter(item => item.id !== id); } 

Here's a simple one liner for removing an object by property from an array of objects.

delete this.items[this.items.findIndex(item => item.item_id == item_id)]; 

or

this.items = this.items.filter(item => item.item_id !== item.item_id); 

Use this, if you need to remove a given object from an array and you want to be sure of the following:

• the list is not reinitialized
• the array length is properly updated

 const objWithIdToRemove; const objIndex = this.objectsArray.findIndex(obj => obj.id === objWithIdToRemove); if (objIndex > -1) { this.objectsArray.splice(objIndex, 1); } 

Multiple options in Typescript/Javascript to remove an element from Array. Splice is the best option as

1. It removes inline without creating a new object
2. It properly updates the length of the array (wont leave blank null element)

Below is an example of removing an object based on some field in a object array using Splice function

const persons = [ { firstName :'John', lastName :'Michel' }, { firstName :'William', lastName :'Scott' }, { firstName :'Amanda', lastName :'Tailor' } ] console.log('Before Deleting :'+JSON.stringify(persons)); console.log('Deleting William:'); persons.splice(persons.findIndex(item => item.firstName === 'William'),1); console.log('After Deleting William'+JSON.stringify(persons));

Answer using TypeScript spread operator (...)

// Your key const key = 'two'; // Your array const arr = [ 'one', 'two', 'three' ]; // Get either the index or -1 const index = arr.indexOf(key); // returns 0 // Despite a real index, or -1, use spread operator and Array.prototype.slice() const newArray = (index > -1) ? [ ...arr.slice(0, index), ...arr.slice(index + 1) ] : arr; 

One more solution using Typescript:

let updatedArray = []; for (let el of this.oldArray) { if (el !== elementToRemove) { updated.push(el); } } this.oldArray = updated; 

let a: number[] = []; a.push(1); a.push(2); a.push(3); let index: number = a.findIndex(a => a === 1); if (index != -1) { a.splice(index, 1); } console.log(a); 

Just wanted to add extension method for an array.

interface Array<T> { remove(element: T): Array<T>; } Array.prototype.remove = function (element) { const index = this.indexOf(element, 0); if (index > -1) { return this.splice(index, 1); } return this; }; 

You can try to get index or position of list or array first, then use for loop to assign current array to a temp list, filter out unwanted item and store wanted item back to original array

removeItem(index) { var tempList = this.uploadFile; this.uploadFile = []; for (var j = 0; j < tempList.length; j++) { if (j != index) this.uploadFile.push(tempList[j]); } } 

We can implement the logic using filter and includes

const checkAlpha2Code = ['BD', 'NZ', 'IN'] let countryAlpha2Code = ['US', 'CA', 'BD', 'NZ', 'AF' , 'AR' , 'BR'] /** * Returns the modified array countryAlpha2Code * after removing elements which matches with the checkAlpha2Code */ countryAlpha2Code = countryAlpha2Code.filter(alpha2code => { return !checkAlpha2Code.includes(alpha2code); }); console.log(countryAlpha2Code) // Output: [ 'US', 'CA', 'AF', 'AR', 'BR' ] // Resetting the values again countryAlpha2Code = ['US', 'CA', 'BD', 'NZ', 'AF' , 'AR' , 'BR'] /** * Returns the modified array countryAlpha2Code * which only matches elements with the checkAlpha2Code */ countryAlpha2Code = countryAlpha2Code.filter(alpha2code => { return checkAlpha2Code.includes(alpha2code); }); console.log(countryAlpha2Code) // Output: [ 'BD', 'NZ' ]

I see many complaints that remove method is not in-built. Consider using Set instead of array - it has add and delete methods in-built.

Similar to Abdus Salam Azad answer , but passing array as parameter from //

function arrayRemove(arr:[], value:any) { return arr.filter(function(ele){ return ele != value; }); }