Optional & Default Parameters

Optional parameters use ? and default parameters use =.

Syntax

TYPESCRIPT

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function greet(name: string, greeting?: string): string {
    return `${greeting || "Hello"}, ${name}!`;
}

function add(a: number, b: number = 10): number {
    return a + b;
}

Optional and Default Parameters

TYPESCRIPT

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function greet(name: string, greeting?: string): string {
    return `${greeting || "Hello"}, ${name}!`;
}

function power(base: number, exp: number = 2): number {
    return base ** exp;
}

console.log(greet("Alice"));
console.log(greet("Bob", "Hi"));
console.log(power(3));
console.log(power(2, 10));

Try It Yourself

Practice

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Exercise

Practice this concept.

Answer

Write the code as shown above.

Quick Quiz

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What did you learn?

Concept A

Concept B

Concept C

Concept D

This covers the basics.

Retry Quiz

Interview Questions

Explain this concept.

It is a fundamental TypeScript feature.

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Function Types

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Rest Parameters