How to create a utility to invert an object? | Frontend Problem Solving | JavaScript Interview Question

In this question, you need to implement a function called invert that takes an object as input parameter and inverts it i.e. return an object where the keys as values and values as keys.

Specifications

• If the input is invalid then the function must throw a TypeError i.e. null/undefined.
• All keys and values are of type String.
• Final object must maintain the original order of the keys.
• Object might contain duplicate values. Handle the duplicate values by appending the original position (index starting from 0) of the key to the value. Please see Syntax section for examples.
• Try to minimise the use of additional space required to create the final object.
• Try to minimise the time complexity.

Syntax

• Without duplicate values

const data = { 'a': 'one', 'b': 'two' };
const inverted = invert(data);

// prints { 'one': 'a', 'two': 1 }
console.log(inverted);

• With duplicate values

const data = { 'a': 'one', 'b': 'one' };
const inverted = invert(data);

// prints { 'one': 'a', 'one_1': 1 }
console.log(inverted);

Submission

Please start the timer before starting and finish your solution within 30-45 mins. Share your solution with us on Twitter or LinkedIn.