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# Module metadata
## Concepts
- [import.meta](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import.meta)
can provide information on the context of the module.
- The boolean
[import.meta.main](https://doc.deno.land/builtin/stable#ImportMeta) will let
you know if the current module is the program entry point.
- The string [import.meta.url](https://doc.deno.land/builtin/stable#ImportMeta)
will give you the URL of the current module.
- The string
[Deno.mainModule](https://doc.deno.land/builtin/stable#Deno.mainModule) will
give you the URL of the main module entry point, i.e. the module invoked by
the deno runtime.
## Example
The example below uses two modules to show the difference between
`import.meta.url`, `import.meta.main` and `Deno.mainModule`. In this example,
`module_a.ts` is the main module entry point:
```ts
/**
* module_b.ts
*/
export function outputB() {
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,
);
}
```
```ts
/**
* module_a.ts
*/
import { outputB } from "./module_b.ts";
function outputA() {
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,
);
}
outputA();
console.log("");
outputB();
```
If `module_a.ts` is located in `/home/alice/deno` then the output of
`deno run --allow-read module_a.ts` is:
```
Module A's import.meta.url file:///home/alice/deno/module_a.ts
Module A's mainModule url file:///home/alice/deno/module_a.ts
Is module A the main module via import.meta.main? true
Module B's import.meta.url file:///home/alice/deno/module_b.ts
Module B's mainModule url file:///home/alice/deno/module_a.ts
Is module B the main module via import.meta.main? false
```
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