String type behavior in Typescript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic type used to represent text in TypeScript?

The string type is used to represent text in TypeScript. It holds sequences of characters.

beginner

Are strings in TypeScript mutable or immutable?

Strings in TypeScript are immutable. Once created, their content cannot be changed directly.

beginner

How can you create a multi-line string in TypeScript?

Use template literals with backticks (``) to create multi-line strings easily.

beginner

What happens when you use the + operator with strings in TypeScript?

The + operator concatenates (joins) two or more strings into one string.

intermediate

How does TypeScript handle string type checking?

TypeScript enforces that variables declared as string can only hold string values, helping catch errors at compile time.

Which of the following is the correct way to declare a string variable in TypeScript?

A let name: string = 'Alice';

B let name = 123;

C let name: number = 'Alice';

D let name: boolean = true;

Option A correctly declares a variable 'name' with type string and assigns a string value.

What will the following code output? <br> let greeting = 'Hello';<br> greeting[0] = 'J';<br> console.log(greeting);

A Jello

B Error

C Hello

D undefined

Strings are immutable, so changing a character by index does nothing. The original string 'Hello' remains.

How do you create a string that spans multiple lines in TypeScript?

A Using double quotes with \n

B Using backticks (template literals)

C Using single quotes with \n

D Using parentheses

Backticks allow multi-line strings directly without needing escape characters.

What is the result of 'Hello' + ' ' + 'World' in TypeScript?

A 'Hello World'

B Error

C 'Hello+World'

D 'HelloWorld'

The + operator concatenates strings, so it joins them with the space in between.

Which of these is NOT a string method in TypeScript?

A includes()

B toUpperCase()

C slice()

D push()

push() is an array method, not a string method.

Explain how strings behave in TypeScript regarding mutability and concatenation.

Think about whether you can change a letter inside a string directly and how to combine strings.

Describe how TypeScript helps ensure variables hold string values and what happens if you assign a different type.

Consider what TypeScript does before running your code to catch mistakes.