Programming TypeScript

Appendix E. Triple-Slash Directives

Triple-slash directives are just regular JavaScript comments that TypeScript looks for to do things like adjust compiler settings for a specific file, or indicate that your file depends on another file. Put your directives at the top of your file, before any code. Triple-slash directives look like this (each directive is a triple-slash, ///, followed by an XML tag):

/// <directive attr="value" />

TypeScript supports a handful of triple-slash directives. Table E-1 lists the ones you are most likely to use:

amd-module

Head over to “The amd-module Directive” to learn more.

lib

The lib directive is a way to indicate to TypeScript which of TypeScript’s libs your module depends on, which you may want to do if your project doesn’t have a tsconfig.json. Declaring the libs you depend on in your tsconfig.json is almost always a better option.

path

When using TSC’s outFile option, use the path directive to declare a dependency on another file, so that the other file appears earlier in your compiled output than the dependent file does. If your project uses imports and exports, you likely won’t ever use this directive.

type

Head over to “The types Directive” to learn more about the type directive.

Table E-1. Triple-slash directives

Directive	Syntax	Use it to…
amd-module	<amd-module name="MyComponent" />	Declare export names when compiling to AMD modules
lib	<reference lib="dom" />	Declare which of TypeScript’s built-in libs your type declarations ...