How to Swap Array Object Values in JavaScript ?

We have given the array of objects, and our task is to swap the values of the object keys present in the array of objects. Below is an example for a better understanding of the problem statement.

Example:

Input: arr = [{a: 1, b: 2}, {a:3, b: 4}]
Output: [ { a: 2, b: 1 }, { a: 4, b: 3 } ]
Explnation: The values of the object keys a and b before swapping 
were 1 and 2 respectively. But after swapping they gets interchanged.

Using Destructuring Assignment

This method uses the for loop to iterate over the array of objects, swapping the values of ‘a’ and ‘b’ properties in each object using the destructuring assignment. Once the swapping is done, we print the swapped values using the log() function.

Example: The below code uses the destructuring assignment to swap array object values using JavaScript.

Javascript

// input arr
let arr = [{a: 1, b: 2}, {a: 3, b: 4}];
console.log("Before Swapping: ", arr);
// swapping using destructuring assignment
for (let i = 0; i < arr.length; i++) {
    [arr[i].a, arr[i].b] = [arr[i].b, arr[i].a];
}
// output arr
console.log("After Swapping: ", arr);

Output

Before Swapping:  [ { a: 1, b: 2 }, { a: 3, b: 4 } ]
After Swapping:  [ { a: 2, b: 1 }, { a: 4, b: 3 } ]

Using Temp Variable

This method uses the temporary variable to swap the values of the array of objects. The loop is used to go over the array of objects, swapping the values of ‘a’ and ‘b‘ properties in each object using the temp variable.

Example: The below code uses the temp variable to swap the array of object values using JavaScript.

Javascript

// input arr of objs
let arr = [{a: 1, b: 2}, {a: 3, b: 4}];
console.log("Before Swapping: ", arr);
// swapping using temp var
for (let i = 0; i < arr.length; i++) {
    let temp = arr[i].a;
    arr[i].a = arr[i].b;
    arr[i].b = temp;
}
// output arr
console.log("After Swapping: ", arr);

Output

Before Swapping:  [ { a: 1, b: 2 }, { a: 3, b: 4 } ]
After Swapping:  [ { a: 2, b: 1 }, { a: 4, b: 3 } ]

Using Array.map() Method

This method uses the Array.map() method to create the new array by swapping the values of each key present in the object. The output consists of the swapped values printed using the log() function.

Example: The below code uses the Array.map() method to swap the array of object values using JavaScript.

Javascript

// arr of objs
let arr = [{a: 1, b: 2}, {a: 3, b: 4}];
console.log("Before Swapping: ", arr);
// swapping values using map()
arr = arr.map(obj => ({a: obj.b, b: obj.a}));
// output arr
console.log("After Swapping: ", arr);

Output

Before Swapping:  [ { a: 1, b: 2 }, { a: 3, b: 4 } ]
After Swapping:  [ { a: 2, b: 1 }, { a: 4, b: 3 } ]

Using Array.forEach() Method

The Array.forEach() method can be used to iterate over the array of objects, then swap the values using the temp variable and the output consists of the modified swapped values of ‘a‘ and ‘b’ properties.

Example: The below code uses the Array.forEach() method to swap the array of object values using JavaScript.

Javascript

// arr of objs
let arr = [{a: 1, b: 2}, {a: 3, b: 4}];
console.log("Before Swapping: ", arr);
// swapping using forEach()
arr.forEach(obj => {
    let temp = obj.a;
    obj.a = obj.b;
    obj.b = temp;
});
// output
console.log("After Swapping: ", arr);

Output

Before Swapping:  [ { a: 1, b: 2 }, { a: 3, b: 4 } ]
After Swapping:  [ { a: 2, b: 1 }, { a: 4, b: 3 } ]