String enums in Typescript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a string enum in TypeScript?

A string enum is a special type in TypeScript where each enum member is initialized with a string literal. It helps group related string constants under one name.

beginner

How do you declare a string enum in TypeScript?

Use the enum keyword followed by member names and assign string values to each member, like:<br>

enum Colors { Red = "RED", Green = "GREEN", Blue = "BLUE" }

intermediate

Why use string enums instead of numeric enums?

String enums provide readable values which make debugging and logging easier. They also avoid accidental numeric value changes and improve code clarity.

intermediate

Can string enum members have computed values?

No, string enum members must be initialized with string literals or other string enum members. Computed or runtime values are not allowed.

beginner

How do you access a string enum member's value?

You access it by using the enum name and member name, like Colors.Red, which returns the string value assigned to that member.

Which of the following is a correct string enum declaration in TypeScript?

A enum Direction { Up = 1, Down = 2 }

B enum Direction { Up, Down }

C enum Direction { Up = true, Down = false }

D enum Direction { Up = "UP", Down = "DOWN" }

Only option C assigns string values to enum members, which is required for string enums.

What will Colors.Green return if enum Colors { Red = "RED", Green = "GREEN" }?

A "GREEN"

B 1

C "Green"

D undefined

The member Green is assigned the string "GREEN", so accessing Colors.Green returns "GREEN".

Can you assign a number to a string enum member?

A Yes, numbers are allowed in string enums.

B No, string enum members must be strings.

C Only if the number is converted to a string.

D Only for the first member.

String enum members must be initialized with string literals, not numbers.

Which is a benefit of using string enums?

A They make code less readable.

B They automatically increment numbers.

C They provide meaningful string values for debugging.

D They allow computed values.

String enums provide clear string values that help with debugging and readability.

Are computed values allowed in string enums?

A No, string enums require string literals.

B Yes, always.

C Only if the computed value is a number.

D Only if the enum is const.

String enums must have string literal values; computed values are not allowed.

Explain what a string enum is and why you might use it in TypeScript.

Think about grouping related strings under one name.

Describe how to declare and access members of a string enum with an example.

Show a simple enum with colors or directions.