ES modules
Export
Export shares functions, classes, and constants from one file. Other files can only use what the source file chooses to export.
export function add(a: number, b: number): number {
return a + b;
}
export const version: string = "1.0";
Import
Import brings exported names into the current file. Named imports list each name in braces and must match the export spelling.
import { add, version } from "./math.js";
console.log(add(2, 3));
console.log(version);
Default exports
A module can have one default export for its main value. Default imports skip the braces and may choose any local name.
export default function greet(name: string): string {
return "Hello " + name;
}
import greet from "./greet.js";
console.log(greet("Ada"));
Extensions in imports
With Node style resolution, relative imports keep the compiled .js extension even though the source file on disk is a .ts file. The compiler maps the .js path back to the matching source.
Write math.js in the import while editing math.ts, and the build will resolve it correctly.
import { add } from "./math.js";
const total = add(2, 3);
console.log(total);
Next: Decorators
Article author: Arthur Isaev
