Junior-Level TypeScript Exam Review

These flashcards cover key concepts, definitions, and example code related to TypeScript as reviewed in the junior-level exam notes.

What is the default type of a variable in TypeScript if no type is assigned?

any

What does the as keyword do in TypeScript?

Casts a value to a specific type.

What is the difference between let and const in TypeScript?

let is for variables that can be changed and are in a local scope, while const is for variables that can't be changed.

What will be the output of the code in question 4?

"five".

How do you define a function that does not return anything?

function logMessage(): void { console.log("Hello"); }

What does ? mean in a function parameter?

It marks the parameter as optional.

How do you create a tuple type in TypeScript?

let myTuple: [string, number] = ["hello", 10];

What is the difference between unknown and any?

unknown is for a variable of which the type is not known, while any can be reassigned to any possible type.

What will happen if you try to reassign a readonly property?

It will throw a compilation error.

What does 'typeof do in TypeScript?

Returns the JavaScript runtime type of a variable.