Modifying array in JavaScript using array method

Question

let fruits = ['apple' , 'cherry', 'grape', undefined, 'lemon' ,'melon'];

i have those array of fruits. i want to replace undefined with another fruit, and return all the array with new fruit included. how to do that using array method in javascript i do need help

Answer 1

You use .splice to replace undefined with new fruit. But just note that it's also possible to achieve it with .map and .filter

let arr = ['apple' , 'cherry', 'grape', undefined, 'lemon' ,'melon'];
 
let index = arr.indexOf(undefined)
arr.splice(index, 1, 'new fruit')
console.log(arr)

Answer 2

You can use Javascript splice method

let fruits = ['apple' , 'cherry', 'grape', undefined, 'lemon' ,'melon'];
fruits.splice(fruits.indexOf(undefined),1,"newFruit")
console.log(fruits)

Answer 3

This is a basic example of what loops are used for. You can use for, or forEach.

let fruits = ['apple' , 'cherry', 'grape', undefined, 'lemon' ,'melon'];
fruits.forEach((fruit,index) => {
 if(fruit == undefined) {
 fruits[index] = 'Some other fruit'
 }
})
console.log(fruits)

• Dedec: thanks, now i know how to use index parameter for looping in forEach

Answer 4

One of ways we can do this is also by using maps as norbekoff told. But the result should be stored in a new Array.If you want to do it inplace then you can go with splice method.

let arr = ['apple' , 'cherry', 'grape', undefined, 'lemon' ,'melon'];
 
let newArr=arr.map((ele)=>{
 if(!ele){
 ele="new Fruit";
 }
 return ele;
 });
 
console.log(newArr);

• Dedec: thanks, another way to find the undefined