</>SkillRecallRECALL WHAT YOU KNOW
Sign in
Explore Library
TypeScriptWorking with JavaScript & Type Declarations

39 items

1

Automatic Type Acquisition

Quiz
2

Typing the global Object

Quiz
3

@ts-check and @ts-nocheck

Quiz
4

@ts-ignore vs @ts-expect-error

Quiz
5

Purpose of Declaration Files

Quiz
6

The declare Keyword

Quiz
7

Ambient Variable and Function Declarations

Quiz
8

Installing @types Packages

Quiz
9

Declaring Untyped Modules

Quiz
10

Gradual JS to TS Migration

Quiz
11

declare namespace Usage

Quiz
12

@param and @type Precision

Quiz
13

JSDoc Type Annotations

Quiz
14

UMD Global Declaration Syntax

Code Quiz
15

JSDoc @type Annotation

Code Quiz
16

JSDoc @param and @returns

Code Quiz
17

Implicit any from JS Import

Code Quiz
18

Overloaded Signatures in .d.ts

Code Quiz
19

declare namespace Members

Code Quiz
20

Ambient const enum

Code Quiz
21

Ambient Class Shape

Code Quiz
22

Ambient Variable with declare

Code Quiz
23

Ambient Function Signature

Code Quiz
24

Value Inside a .d.ts File

Code Quiz
25

Triple-Slash Reference Syntax

Code Quiz
26

Installing @types Packages

Code Quiz
27

Ambient Global Variables

Flashcard
28

Ambient Functions

Flashcard
29

JSDoc for Typing JavaScript

Flashcard
30

@ts-ignore vs @ts-expect-error

Flashcard
31

Triple-Slash Directives

Flashcard
32

The declare Keyword

Flashcard
33

@ts-check and @ts-nocheck

Flashcard
34

Global Augmentation with declare global

Flashcard
35

Gradual JS to TS Migration

Flashcard
36

Structure of an @types Package

Flashcard
37

Wildcard Module Declarations

Flashcard
38

Handling Implicit any

Flashcard
39

Installing @types Packages

Flashcard
Code QuizIntermediate

Implicit any from JS Import

Diagnose why an import from a plain JS module has no type safety.

Codetypescript
// legacy.js has no accompanying .d.ts file
import { calculate } from './legacy';

// expected a number, but this compiles without complaint
const result: number = calculate('not', 'numbers');

Why does this unsafe call compile without a type error?