Generic ImportMap class utility for the manipulation and resolution of import maps, used by JSPM.
Node.js:
npm install @jspm/import-map
Browser:
const { ImportMap } = await import('https://jspm.dev/@jspm/import-map');
@jspm/import-map
only ships as an ES module, so to use it in Node.js add "type": "module"
to your package.json file or write an .mjs
to load it.
example.mjs
import { ImportMap } from '@jspm/import-map';
// Must pass a full URL as a base URL for the map
const mapBase = new URL('.', import.meta.url);
const map = new ImportMap(mapBase, {
imports: {
react: 'https://cdn.com/react.js'
},
scopes: {
'https://site.com/': {
react: 'https://cdn.com/react2.js'
}
}
});
// Use the map resolver
map.resolve('react', mapBase) === 'https://cdn.com/react.js';
map.resolve('react', 'https://site.com/') === 'https://cdn.com/react2.js';
// Supports normal URL resolution behaving a browser-compatible ES module resolver
map.resolve('./hello.js', 'https://site.com/') === 'https://site.com/hello.js';
// Mutate the map
map.set('react', './custom-react.js');
map.resolve('react') === new URL('./custom-react.js', mapBase).href;
// Mutate the map inside a custom scope
map.set('react', './custom-react2.js', 'https://another.com/');
map.resolve('react', 'https://another.com/') === new URL('./custom-react2.js', mapBase).href;
// Get the map JSON
console.log(JSON.stringify(map.toJSON(), null, 2));
// {
// "imports": {
// "react": "./custom-react.js"
// },
// "scopes": {
// "https://site.com/": {
// "react": "https://cdn.com/react2.js"
// },
// "https://another.com/": {
// "react": "./custom-react2.js"
// }
// }
// }
// Rebase the map
map.rebase('./map/');
console.log(JSON.stringify(map.toJSON(), null, 2));
// {
// "imports": {
// "react": "../custom-react.js"
// },
// "scopes": {
// "https://site.com/": {
// "react": "https://cdn.com/react2.js"
// },
// "https://another.com/": {
// "react": "../custom-react2.js"
// }
// }
// }
// Flatten the import map (removes unnecessary scope redundancy)
map.set('react', '../custom-react.js', 'https://site.com/');
map.flatten();
console.log(JSON.stringify(map.toJSON(), null, 2));
// {
// "imports": {
// "react": "../custom-react.js"
// },
// "scopes": {
// "https://another.com/": {
// "react": "../custom-react2.js"
// }
// }
// }
// Replace URLs in the map
map.replace('https://cdn.com/', 'https://cdn-mirror.com/');
map.replace('https://another.com/', 'https://another-site.com/');
console.log(JSON.stringify(map.toJSON(), null, 2));
// {
// "imports": {
// "react": "../custom-react.js"
// },
// "scopes": {
// "https://another-site.com/": {
// "react": "../custom-react2.js"
// }
// }
// }
See map.d.ts.
Support is also provided for conditional maps supporting a way to manage generic maps for multiple environment targets, before serializing or resolving for exact environment targets.
All pull requests welcome!
MIT