TypeScript Strict Mode and Why It Matters - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is TypeScript strict mode?

TypeScript strict mode is a setting that makes the compiler check your code more carefully to catch more mistakes early.

beginner

Name two benefits of using TypeScript strict mode.

1. It helps find bugs before running the code.<br>2. It makes your code safer and easier to understand.

intermediate

What does the 'noImplicitAny' option do in strict mode?

It stops TypeScript from assuming a variable has type 'any' when you don't specify a type, forcing you to be explicit.

intermediate

How does strict mode help with null and undefined values?

Strict mode includes checks that make you handle null and undefined values explicitly, reducing runtime errors.

beginner

How do you enable strict mode in a TypeScript project?

You add "strict": true in the tsconfig.json file under the compilerOptions section.

What happens if you enable strict mode in TypeScript?

A The compiler checks your code more strictly for errors.

B The code runs faster in the browser.

C You can write JavaScript without types.

D The compiler ignores type errors.

Strict mode makes the compiler check your code more carefully to catch errors early.

Which option is part of TypeScript strict mode?

A outDir

B allowJs

C noImplicitAny

D removeComments

noImplicitAny is a strict mode option that prevents implicit 'any' types.

Why is handling null and undefined important in strict mode?

A To allow variables to be any type.

B To make the code run slower.

C To disable type checking.

D To avoid runtime errors caused by unexpected null or undefined values.

Strict mode forces you to handle null and undefined explicitly to prevent errors when the code runs.

How do you turn on strict mode in a TypeScript project?

A Set "strict": true in tsconfig.json.

B Add "use strict" at the top of every file.

C Install a special strict mode package.

D Use the --no-strict flag when compiling.

Strict mode is enabled by setting "strict": true in the tsconfig.json file.

What is a downside of strict mode?

A It makes your code run slower.

B You need to write more explicit types.

C It disables type checking.

D It removes support for JavaScript.

Strict mode requires you to be more explicit with types, which can take more time but improves code quality.

Explain what TypeScript strict mode is and why it is useful.

Think about how strict mode changes the way TypeScript checks your code.

Describe how strict mode affects handling of null and undefined values in TypeScript.

Consider what happens if you forget to check for null or undefined without strict mode.