Support asset imports (#9)

README.md

@@ -239,6 +239,20 @@ Options include:
 }
 ```
 
+#### `const url = Module.asset(specifier, parentURL[, options])`
+
+Options include:
+
+```js
+{
+  referrer = null,
+  protocol,
+  imports,
+  resolutions,
+  conditions
+}
+```
+
 #### `module.url`
 
 #### `module.filename`

index.js

@@ -324,6 +324,7 @@ const Module = module.exports = exports = class Module {
     meta.cache = module._cache
     meta.resolve = resolve
     meta.addon = addon
+    meta.asset = asset
 
     function resolve (specifier) {
       const resolved = self.resolve(specifier, referrer._url, { referrer })
@@ -341,6 +342,10 @@ const Module = module.exports = exports = class Module {
 
       return addon._exports
     }
+
+    function asset (specifier) {
+      return self.asset(specifier, referrer._url, { referrer }).href
+    }
   }
 
   static _onrun (reason, promise, err = reason) {
@@ -489,6 +494,46 @@ const Module = module.exports = exports = class Module {
     }
   }
 
+  static asset (specifier, parentURL, opts = {}) {
+    const self = Module
+
+    if (typeof specifier !== 'string') {
+      throw new TypeError(`Specifier must be a string. Received type ${typeof specifier} (${specifier})`)
+    }
+
+    const {
+      referrer = null,
+      protocol = referrer ? referrer._protocol : self._protocol,
+      imports = referrer ? referrer._imports : null,
+      resolutions = referrer ? referrer._resolutions : null,
+      conditions = referrer ? referrer._conditions : self._conditions
+    } = opts
+
+    const [resolution = null] = resolve(specifier, parentURL, {
+      conditions,
+      imports,
+      resolutions
+    }, readPackage)
+
+    if (resolution !== null && protocol.exists(resolution)) {
+      return protocol.asset(resolution)
+    }
+
+    let msg = `Cannot find asset '${specifier}'`
+
+    if (referrer) msg += ` imported from '${referrer._url.href}'`
+
+    throw errors.ASSET_NOT_FOUND(msg)
+
+    function readPackage (packageURL) {
+      if (protocol.exists(packageURL)) {
+        return Module.load(packageURL, { protocol })._exports
+      }
+
+      return null
+    }
+  }
+
   static _extensionFor (type) {
     switch (type) {
       case constants.types.SCRIPT:
@@ -568,6 +613,7 @@ const createRequire = exports.createRequire = function createRequire (parentURL,
   require.cache = module._cache
   require.resolve = resolve
   require.addon = addon
+  require.asset = asset
 
   return require
 
@@ -595,6 +641,10 @@ const createRequire = exports.createRequire = function createRequire (parentURL,
 
     return addon._exports
   }
+
+  function asset (specifier) {
+    return urlToPath(self.asset(specifier, referrer._url, { referrer }))
+  }
 }
 
 if (Bare.simulator) Module._conditions.push('simulator')

lib/errors.js

@@ -16,6 +16,10 @@ module.exports = class ModuleError extends Error {
     return new ModuleError(msg, 'MODULE_NOT_FOUND', ModuleError.MODULE_NOT_FOUND)
   }
 
+  static ASSET_NOT_FOUND (msg) {
+    return new ModuleError(msg, 'ASSET_NOT_FOUND', ModuleError.ASSET_NOT_FOUND)
+  }
+
   static UNKNOWN_PROTOCOL (msg) {
     return new ModuleError(msg, 'UNKNOWN_PROTOCOL', ModuleError.UNKNOWN_PROTOCOL)
   }

lib/protocol.js

@@ -6,7 +6,8 @@ module.exports = class ModuleProtocol {
       'resolve',
       'exists',
       'read',
-      'load'
+      'load',
+      'asset'
     ]) {
       const method = methods[name]
 
@@ -40,6 +41,10 @@ module.exports = class ModuleProtocol {
     return null
   }
 
+  asset (url) {
+    return url
+  }
+
   extend (methods) {
     return new ModuleProtocol(methods, this)
   }

package.json

@@ -26,7 +26,7 @@
   },
   "homepage": "https://github.com/holepunchto/bare-module#readme",
   "dependencies": {
-    "bare-bundle": "^1.0.0",
+    "bare-bundle": "^1.3.0",
     "bare-module-resolve": "^1.6.0",
     "bare-path": "^3.0.0",
     "bare-url": "^2.0.1",

test.js

@@ -2585,6 +2585,126 @@ test('extend the default protocol', (t) => {
   t.is(Module.load(pathToFileURL('test/fixtures/foo.js'), { protocol }).exports, 'modified')
 })
 
+test('load .js with asset import', (t) => {
+  t.teardown(onteardown)
+
+  const protocol = new Module.Protocol({
+    exists (url) {
+      return url.href === root + '/foo.txt'
+    },
+
+    read (url) {
+      if (url.href === root + '/index.js') {
+        return 'module.exports = require.asset(\'./foo.txt\')'
+      }
+
+      t.fail()
+    }
+  })
+
+  t.is(Module.load(new URL(root + '/index.js'), { protocol }).exports, isWindows ? 'c:\\foo.txt' : '/foo.txt')
+})
+
+test('load .cjs with asset import', (t) => {
+  t.teardown(onteardown)
+
+  const protocol = new Module.Protocol({
+    exists (url) {
+      return url.href === root + '/foo.txt'
+    },
+
+    read (url) {
+      if (url.href === root + '/index.cjs') {
+        return 'module.exports = require.asset(\'./foo.txt\')'
+      }
+
+      t.fail()
+    }
+  })
+
+  t.is(Module.load(new URL(root + '/index.cjs'), { protocol }).exports, isWindows ? 'c:\\foo.txt' : '/foo.txt')
+})
+
+test('load .mjs with asset import', (t) => {
+  t.teardown(onteardown)
+
+  const protocol = new Module.Protocol({
+    exists (url) {
+      return url.href === root + '/foo.txt'
+    },
+
+    read (url) {
+      if (url.href === root + '/index.mjs') {
+        return 'export default import.meta.asset(\'./foo.txt\')'
+      }
+
+      t.fail()
+    }
+  })
+
+  t.is(Module.load(new URL(root + '/index.mjs'), { protocol }).exports.default, root + '/foo.txt')
+})
+
+test('load .js with asset import, asset method', (t) => {
+  t.teardown(onteardown)
+
+  const protocol = new Module.Protocol({
+    exists (url) {
+      return url.href === root + '/foo.txt'
+    },
+
+    read (url) {
+      if (url.href === root + '/index.js') {
+        return 'module.exports = require.asset(\'./foo.txt\')'
+      }
+
+      t.fail()
+    },
+
+    asset (url) {
+      if (url.href === root + '/foo.txt') {
+        return new URL(root + '/bar.txt')
+      }
+
+      return url
+    }
+  })
+
+  t.is(Module.load(new URL(root + '/index.js'), { protocol }).exports, isWindows ? 'c:\\bar.txt' : '/bar.txt')
+})
+
+test('load .bundle with asset import', (t) => {
+  t.teardown(onteardown)
+
+  const bundle = new Module.Bundle()
+    .write('/foo.js', 'module.exports = require.asset(\'./bar.txt\')', { main: true })
+    .write('/bar.txt', 'hello world', { asset: true })
+    .toBuffer()
+
+  t.is(Module.load(new URL(root + '/app.bundle'), bundle).exports, isWindows ? 'c:\\app.bundle\\bar.txt' : '/app.bundle/bar.txt')
+})
+
+test('load .bundle with asset import, asset method', (t) => {
+  t.teardown(onteardown)
+
+  const bundle = new Module.Bundle()
+    .write('/foo.js', 'module.exports = require.asset(\'./bar.txt\')', { main: true })
+    .write('/bar.txt', 'hello world', { asset: true })
+    .toBuffer()
+
+  const protocol = new Module.Protocol({
+    asset (url) {
+      if (url.href === root + '/app.bundle/bar.txt') {
+        return new URL(root + '/bar.txt')
+      }
+
+      return url
+    }
+  })
+
+  t.is(Module.load(new URL(root + '/app.bundle'), bundle, { protocol }).exports, isWindows ? 'c:\\bar.txt' : '/bar.txt')
+})
+
 function onteardown () {
   // TODO Provide a public API for clearing the cache.
   Module._cache = Object.create(null)