Create Hello World Function

Create Hello World Function

What is this problem about?

The Create Hello World Function interview question is a very simple JavaScript problem. You need to write a function that returns another function. This returned function, no matter what arguments it receives, should always return the string "Hello World".

Why is this asked in interviews?

Companies like Apple, Uber, and Microsoft use this coding problem as an initial sanity check for candidates interviewing for frontend or full-stack roles. It assesses your understanding of basic JavaScript syntax, specifically higher-order functions and rest parameters (...args). It's a "level 0" problem intended to put candidates at ease before moving to more difficult topics.

Algorithmic pattern used

This problem uses the Higher-Order Function pattern.

1. Define a function createHelloWorld.
2. Return an inner function (anonymous or named).
3. Use the rest parameter syntax (...args) to show that the function accepts any number of arguments.
4. Inside the inner function, return the literal string "Hello World".

Example explanation

const f = createHelloWorld();
f(); // Returns "Hello World"
f(1, 2, 3); // Returns "Hello World"
f({}, null, "test"); // Returns "Hello World"

The inner function ignores the 1, 2, 3 or any other input and simply executes its hardcoded return statement.

Common mistakes candidates make

• Returning the string directly: Returning the string from createHelloWorld instead of returning a function that returns the string.
• Incorrect Spelling: Misspelling "Hello World" or missing the capitalization.
• Fixed Arguments: Writing the inner function to take exactly zero arguments, which might fail tests that pass arbitrary values to it.

Interview preparation tip

Higher-order functions are essential in JavaScript (think map, filter, reduce). Even for a simple problem like this, be ready to explain the concept of "functions as first-class citizens."