Build modules are separate logical units that can export values. Build projects can import values from one or more build modules. Only values with 'public' visibility can be exported/imported.

Import

There are two ways to import values from a module:

• in a declaration (import { X } from "MyModule"), and
• within an expression (importFrom("MyModule").X).

The import declaration

Values may be imported from one or more modules at the top of a project definition. This is recommended when the imported value is used multiple times in the same project.

Standard import declaration

import * as Compression from "compression";
const zipArchive = Compression.Zip.pack([ f`file.txt` ]]);

Selective import declaration

import {Zip} from "compression";
const zipArchive = Zip.pack([ f`file.txt` ]);

Multiple selective import declaration

import {Zip, Gzip} from "compression";
const zipArchive = Zip.pack([ f`file.txt` ]);
const gzipArchive = Gzip.pack([ f`file.txt` ]);

Aliased selective import declaration

import {Zip as FastZip} from "compression";
const zipArchive = FastZip.pack([ f`file.txt` ]);

Aliased multiple selective import declaration

import {Zip as FastZip, GZip as GZ} from "compression";
const zipArchive = FastZip.pack([ f`file.txt` ]);
const gzip = GZ.pack([ f`file.txt` ]);

The importFrom expression

Elements from other modules may be imported within an expression using the importFrom function. This function takes the module's name (as a string value) to import and returns an object with all values exported by the selected module.

const zipArchive = importFrom("compression").Zip.pack([ f`file.txt` ]);

Note: Consider using a single import declaration at the file's top if you find yourself overusing importFrom with the same module in a single file.

Export

Declarations in a build project file are not visible to other projects unless they are explicitly exported with an export declaration. The declaration must also be marked as public with the @@public decorator to be visible to other modules.

Re-export a whole module

export * from "compression";

Selective re-export

export { Zip } from "compression";

Multiple selective re-export

export { Zip, Gzip } from "compression";

Aliased selective re-export

export { Zip as FastZip } from "compression";

Aliased multiple selective re-export

export { Zip as FastZip, Gzip as GZ } from "compression";

Exporting values

export const myValue = 42;

const myObject = { "foo": "bar" };
export { myObject };

Exporting imported values

import * as Compression from "compression";
import { Zip, Gzip as GZ } from "compression";

export { Compression, Zip, GZ as MyGZ };
export const gzipArchive = GZ.pack([ f`file.txt` ]);