Triple-slash directive
- TypeScript course
- Intermediate
- Lesson 60/89
- 4 min
Learn triple-slash directives.
What is a triple-slash directive?
A triple-slash directive is a single-line comment that gives special instructions to the compiler. It starts with /// and is processed differently from a normal // comment. Its most common use is /// <reference path="..." /> to reference another .d.ts file.
/// <reference path="./types.d.ts" />Other reference directives
The reference directive has different attributes. The types attribute specifies which @types packages to include. The lib attribute specifies which built-in lib files to include.
/// <reference types="node" />
/// <reference lib="es2020" />Practice Reference the math.d.ts file
Use /// <reference path="./math.d.ts" /> to reference the math.d.ts file. Then print "başvuruldu" with console.log.
Starter code
// math.d.ts dosyasına triple-slash yönergesi ile başvur
console.log("başvuruldu");Sample solution
/// <reference path="./math.d.ts" />
console.log("başvuruldu");Expected output
başvuruldu
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 How many slashes must a triple-slash directive start with?
- Four slashes (////)
- Single slash (/)
- Three slashes (///) Correct answer
- Two slashes (//)
Explanation: A triple-slash directive starts with exactly three slashes (///); two slashes is a normal comment.
2 reference directive tag
/// <____ path="./types.d.ts" />/// <reference path="./types.d.ts" />Explanation: The tag name of the triple-slash reference directive is `reference`; it takes path, types or lib attributes.
3 Triple-slash directives
| Term | Meaning |
|---|---|
path |
File path attribute |
types |
Type package attribute |
lib |
Built-in library attribute |
/// |
Directive prefix |