String.prototype.padStart() — JS Technical Interview Questions & Answers

Pads the start of a string to a target length.

String.prototype.padStart()

  • String.prototype.padStart() is a JS topic. In plain words you use it for class Student in a tiny OOP file. Don’t start with a slogan — start with that picture.
  • Smallest example: class Student { constructor(name) {} }. Type it, run it, and say what you see. If you can do that from memory, you know String.prototype.padStart().
  • From the example next to this theory: Pads the start of a string to a target length.
  • Trap: arrow function for a method that needs this. Fix that before you talk about advanced JS.
  • Viva: what is String.prototype.padStart()? Then show class Student { constructor(name) {} }. Then name the trap.

Technical Interview Tip: What is String.prototype.padStart()? Show this: class Student { constructor(name) {} }. Trap: arrow function for a method that needs this.

Code Examples for String.prototype.padStart()

String.prototype.padStart() — working example

// Topic: String.prototype.padStart()
const nums = [1, 2, 3];
const doubled = nums.map((n) => n * 2);
console.log(doubled);
console.log(doubled.reduce((a, b) => a + b, 0));

String.prototype.padStart(): map then reduce on [1, 2, 3]. Say both prints.

How to Explain String.prototype.padStart() to an Interviewer

What is String.prototype.padStart()?

Used for class Student a tiny OOP file Not just the heading

Give one small example of String.prototype.padStart().

class Student { constructor(name) {} } Pads the start of a string to a target length

What mistake do beginners make with String.prototype.padStart()?

arrow function for a method that needs this Show the fix

Where do you use String.prototype.padStart()?

a tiny OOP file class Student