CODEWITHSUNDEEP
javascriptarraysobject
Anon Symphony
Anon Symphony

Reputation: 47

Place a null at the beginning of an Array

I have a code that turns array into array objects

const thisArray = ['1', '2'];

Below is my function that converts it:

function macsFunction(codes){
  const mappedObjects = codes.map(code => {
    return {
    '0': Number(code),
    '1': 'Car'
     };
  });
 return mappedObjects;
}


const thisSay = macsFunction(thisArray);

console.log(thisSay);

The result is like this:

[ { '0': 5, '1': 'Car' }, { '0': 13, '1': 'Car' } ]

Now it's been a long hours i wanted to achieve something like :

[null, { '0': 5, '1': 'Car' }, { '0': 13, '1': 'Car' } ]

I want to place a null at the beginning of the array. But I've tried concat, fill, unshift. It doesn't work. Happy to see if someone could help.

Upvotes: 0

Views: 114

Answers (2)

saucel
saucel

Reputation: 96

You can use the unshift method to add something to the beginning of an array.

Documentation can be found here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/unshift

Upvotes: 0

Mamun
Mamun

Reputation: 68933

You can use Array.prototype.unshift() which adds one or more elements to the beginning of an array:

const thisArray = ['1', '2'];

function macsFunction(codes){
  const mappedObjects = codes.map(code => {
    return {
    '0': Number(code),
    '1': 'Car'
     };
  });
 mappedObjects.unshift(null);
 return mappedObjects;
}


const thisSay = macsFunction(thisArray);

console.log(thisSay);

Upvotes: 2

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