Namespace declaration in Typescript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a namespace in TypeScript?

A namespace is a way to group related code like variables, functions, and classes under a single name to avoid name conflicts and organize code.

beginner

How do you declare a namespace in TypeScript?

Use the <code>namespace</code> keyword followed by the namespace name and curly braces containing the code to group.<br>Example:<br><pre>namespace MyNamespace {
  export function greet() { console.log('Hello'); }
}</pre>

beginner

Why do we use the export keyword inside a namespace?

To make functions, classes, or variables accessible outside the namespace, you must mark them with export. Otherwise, they stay private inside the namespace.

beginner

How do you access a function inside a namespace?

Use the namespace name followed by a dot and the function name.<br>Example:<br>

MyNamespace.greet();

intermediate

Can namespaces be split across multiple files in TypeScript?

Yes, namespaces can be split into multiple files by declaring the same namespace name in each file. When compiled, TypeScript merges them into one namespace.

What keyword is used to declare a namespace in TypeScript?

A namespace

B module

C package

D class

The namespace keyword is used to declare a namespace in TypeScript.

How do you make a function inside a namespace accessible outside it?

A Use the <code>private</code> keyword

B Use the <code>public</code> keyword

C Use the <code>export</code> keyword

D No special keyword needed

Functions must be marked with export inside a namespace to be accessible outside.

How do you call a function named sayHi inside a namespace Greetings?

A sayHi.Greetings()

B sayHi()

C Greetings->sayHi()

D Greetings.sayHi()

You call it by prefixing with the namespace name: Greetings.sayHi().

Can namespaces help avoid name conflicts in large projects?

A Only if you use modules

B Yes, by grouping code under unique names

C Only if you use classes

D No, namespaces increase conflicts

Namespaces group related code and prevent name conflicts by creating unique scopes.

Are namespaces the same as ES6 modules in TypeScript?

A No, namespaces are internal grouping, modules are file-based

B Namespaces are deprecated modules

C Yes, they are identical

D Modules are a type of namespace

Namespaces are internal code grouping, while modules are based on files and imports/exports.

Explain what a namespace is and why it is useful in TypeScript.

Think about how you keep things organized in a big project.

Describe how to declare a namespace and access a function inside it.

Remember the syntax and how to reach inside the namespace.