How to replace an item in an array with JavaScript?

Question

Each item of this array is some number.

var items = Array(523,3452,334,31, ...5346);

How do I replace some number in with array with a new on

Answer 1

Here is the basic answer made into a reusable function:

function arrayFindReplace(array, findValue, replaceValue){
    while(array.indexOf(findValue) !== -1){
        let index = array.indexOf(findValue);
        array[index] = replaceValue;
    }
}

Answer 2

ES6 way:

const items = Array(523, 3452, 334, 31, ...5346);

We wanna replace 3452 with 1010, solution:

const newItems = items.map(item => item === 3452 ? 1010 : item);

Surely, the question is for many years ago and for now I just prefer to use immutable solution, definitely, it is awesome for ReactJS.

For frequent usage I offer below function:

const itemReplacer = (array, oldItem, newItem) =>
  array.map(item => item === oldItem ? newItem : item);

Answer 3

A functional approach to replacing an element of an array in javascript:

const replace = (array, index, ...items) => [...array.slice(0, index), ...items, ...array.slice(index + 1)];

Answer 4

First method

Best way in just one line to replace or update item of array

array.splice(array.indexOf(valueToReplace), 1, newValue)

Eg:

let items = ['JS', 'PHP', 'RUBY'];

let replacedItem = items.splice(items.indexOf('RUBY'), 1, 'PYTHON')

console.log(replacedItem) //['RUBY']
console.log(items) //['JS', 'PHP', 'PYTHON']

Second method

An other simple way to do the same operation is :

items[items.indexOf(oldValue)] = newValue

Answer 5

Here attached the code which replace all items in array

var temp_count=0;
layers_info_array.forEach(element => {
     if(element!='')element=JSON.parse(element);//change this line if you want other change method, here I changed string to object
     layers_info_array[temp_count]=element;
     temp_count++;
});

Answer 6

Well if anyone is interresting on how to replace an object from its index in an array, here's a solution.

Find the index of the object by its id:

const index = items.map(item => item.id).indexOf(objectId)

Replace the object using Object.assign() method:

Object.assign(items[index], newValue)