For this, use Object.assign(). Following is the code −
Example
const details = {john:{'studentName':'John'},david:{'studentName':'David'},mike:{'studen tName':'Mike'},bob:{'studentName':'Bob'},carol:{'studentName':'Carol'}}, join_values = ['David', 'Carol'], output = Object.assign( {}, ...Object .keys(details) .map(key => ({[key]: { ...details[key], lastName: join_values.includes(details[key].studentName) ? 'Miller' : 'Smith' }}))) console.log(output)
To run the above program, you need to use the following command −
node fileName.js.
Output
Here, my file name is demo157.js. This will produce the following output −
PS C:\Users\Amit\JavaScript-code> node demo157.js { john: { studentName: 'John', lastName: 'Smith' }, david: { studentName: 'David', lastName: 'Miller' }, mike: { studentName: 'Mike', lastName: 'Smith' }, bob: { studentName: 'Bob', lastName: 'Smith' }, carol: { studentName: 'Carol', lastName: 'Miller' } }