Different ways to add a new property using the JavaScript spread operator

Question

Different ways to add a new property using the JavaScript spread operator

Looking to enhance an existing array of objects by adding a new object:

const oldArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const newArray = [...oldArray, { name: 'Fourth', value: 'four' }]

The goal is to arrange newArray so that the Fourth object is placed as the 3rd item (index 2) in oldArray. Is there a way to configure newArray so that the new object is inserted as the 3rd item in the ...oldArray spread operator, without needing to rewrite all of the items in oldArray in newArray?

javascript arrays sorting object spread-syntax

Answer 1

Answer №1

To utilize the spread syntax in combination with the .slice() method, follow this example.

const originalArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const modifiedArray = [...originalArray.slice(0, 2), { name: 'Fourth', value: 'four' }, ...originalArray.slice(2)];

console.log(modifiedArray);

Answer 2

To utilize the spread syntax in combination with the .slice() method, follow this example.

const originalArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const modifiedArray = [...originalArray.slice(0, 2), { name: 'Fourth', value: 'four' }, ...originalArray.slice(2)];

console.log(modifiedArray);

Answer 3

Answer №2

To achieve the desired outcome, you have two options when working with arrays in JavaScript.

const oldArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const newArray = [...oldArray.slice(0,2), { name: 'Fourth', value: 'four' }, ...oldArray.slice(2)]

console.log(newArray.map(x => x.name));

The other approach involves using the splice() method instead.

const oldArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const newArray = [...oldArray]
newArray.splice(2,0,{ name: 'Fourth', value: 'four' });

console.log(newArray.map(x => x.name));

Answer 4

To achieve the desired outcome, you have two options when working with arrays in JavaScript.

const oldArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const newArray = [...oldArray.slice(0,2), { name: 'Fourth', value: 'four' }, ...oldArray.slice(2)]

console.log(newArray.map(x => x.name));

The other approach involves using the splice() method instead.

const oldArray = [{ name: 'First', value: 'one' }, { name: 'Second', value: 'two' }, { name: 'Third', value: 'three' }]
const newArray = [...oldArray]
newArray.splice(2,0,{ name: 'Fourth', value: 'four' });

console.log(newArray.map(x => x.name));

Different ways to add a new property using the JavaScript spread operator

Answer №1

Answer №2

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