Module metadata

ConceptsJump to heading#

• import.metacan provide information on the context of the module.
• The booleanimport.meta.mainwill let you know if the current module is the program entry point.
• The stringimport.meta.urlwill give you the URL of the current module.
• The stringimport.meta.filenamewill give you the fully resolved path to the current module.For localmodules only.
• The stringimport.meta.dirnamewill give you the fully resolved path to the directory containing the currentmodule.For local modules only.
• Theimport.meta.resolveallows you to resolve specifier relative to the current module. This functiontakes into account an import map (if one was provided on startup).
• The stringDeno.mainModulewill give you the URL of the main module entry point, i.e. the module invokedby the deno runtime.

ExampleJump to heading#

The example below uses two modules to show the difference betweenimport.meta.url,import.meta.main andDeno.mainModule. In this example,module_a.ts is the main module entry point:

exportfunctionoutputB(){console.log("Module B's import.meta.url",import.meta.url);console.log("Module B's mainModule url", Deno.mainModule);console.log("Is module B the main module via import.meta.main?",import.meta.main,);}

import{ outputB}from"./module_b.ts";functionoutputA(){console.log("Module A's import.meta.url",import.meta.url);console.log("Module A's mainModule url", Deno.mainModule);console.log("Is module A the main module via import.meta.main?",import.meta.main,);console.log("Resolved specifier for ./module_b.ts",import.meta.resolve("./module_b.ts"),);}outputA();console.log("");outputB();

Ifmodule_a.ts is located in/home/alice/deno then the output ofdeno run --allow-read module_a.ts is:

Module A's import.meta.url file:///home/alice/deno/module_a.tsModule A's mainModule url file:///home/alice/deno/module_a.tsIs module A the main module via import.meta.main? trueResolved specifier for ./module_b.ts file:///home/alice/deno/module_b.tsModule B's import.meta.url file:///home/alice/deno/module_b.tsModule B's mainModule url file:///home/alice/deno/module_a.tsIs module B the main module via import.meta.main? false