worker_threads: add support for data URLs

doc/api/worker_threads.md

@@ -588,7 +588,8 @@ changes:
 * `filename` {string|URL} The path to the Worker’s main script or module. Must
   be either an absolute path or a relative path (i.e. relative to the
   current working directory) starting with `./` or `../`, or a WHATWG `URL`
-  object using `file:` protocol.
+  object using `file:` or `data:` protocol.
+  When using a [`data:` URL][], you must set the `type` option to `"module"`.
   If `options.eval` is `true`, this is a string containing JavaScript code
   rather than a path.
 * `options` {Object}
@@ -601,12 +602,13 @@ changes:
     to specify that the parent thread and the child thread should share their
     environment variables; in that case, changes to one thread’s `process.env`
     object will affect the other thread as well. **Default:** `process.env`.
-  * `eval` {boolean} If `true`, interpret the first argument to the constructor
+  * `eval` {boolean} If `true`, interprets the first argument to the constructor
     as a script (or a module if `type` is set to `module`) that is executed once
     the worker is online.
-  * `type` {string} If `"module"` and `eval` is set to `true`, interpret the
-    first argument as an ECMAScript 2015 module instead of a script. The default
-    value is `"classic"`. Doesn't have any effect when `eval` is set to `false`.
+  * `type` {string} If `"module"`, interprets the first argument as an
+    ECMAScript 2015 module instead of a script. The default value is
+    `"classic"`. Doesn't have any effect when `filename` refers to a file, in
+    which case the type is inferred from the file extension.
   * `execArgv` {string[]} List of node CLI options passed to the worker.
     V8 options (such as `--max-old-space-size`) and options that affect the
     process (such as `--title`) are not supported. If set, this will be provided
@@ -869,3 +871,4 @@ active handle in the event system. If the worker is already `unref()`ed calling
 [child processes]: child_process.html
 [contextified]: vm.html#vm_what_does_it_mean_to_contextify_an_object
 [v8.serdes]: v8.html#v8_serialization_api
+[`data:` URL]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs

lib/internal/worker.js

@@ -4,6 +4,7 @@
 
 const {
   ArrayIsArray,
+  JSONStringify,
   MathMax,
   ObjectCreate,
   ObjectEntries,
@@ -99,7 +100,7 @@ class Worker extends EventEmitter {
       argv = options.argv.map(String);
     }
 
-    let url;
+    let url, doEval;
     if (options.eval) {
       if (typeof filename !== 'string') {
         throw new ERR_INVALID_ARG_VALUE(
@@ -109,7 +110,20 @@ class Worker extends EventEmitter {
         );
       }
       url = null;
+      doEval = true;
+    } else if (filename?.protocol === 'data:') {
+      if (options.type !== 'module') {
+        throw new ERR_INVALID_ARG_VALUE(
+          'options.type',
+          options.type,
+          'must be set to "module" when filename is a data: URL'
+        );
+      }
+      url = null;
+      doEval = true;
+      filename = `import ${JSONStringify(filename)}`;
     } else {
+      doEval = false;
       if (isURLInstance(filename)) {
         url = filename;
         filename = fileURLToPath(filename);
@@ -207,7 +221,7 @@ class Worker extends EventEmitter {
       argv,
       type: messageTypes.LOAD_SCRIPT,
       filename,
-      doEval: !!options.eval,
+      doEval,
       workerType: options.type,
       cwdCounter: cwdCounter || workerIo.sharedCwdCounter,
       workerData: options.workerData,

test/parallel/test-worker-eval.js

@@ -10,6 +10,8 @@ const cjsLoadingESMError = /Unexpected token 'export'/;
 const esmLoadingCJSError = /module is not defined/;
 const invalidValueError =
   /The argument 'options\.type' must be either "module" or "classic"/;
+const invalidValueError2 =
+  /The argument 'options\.type' must be set to "module" when filename is a data: URL/;
 
 function runInWorker(evalString, options) {
   return new Promise((resolve, reject) => {
@@ -19,20 +21,42 @@ function runInWorker(evalString, options) {
   });
 }
 
-let options;
+{
+  const options = { eval: true };
+  assert.rejects(runInWorker(moduleString, options), cjsLoadingESMError);
+  runInWorker(cjsString, options); // does not reject
+}
 
-options = { eval: true };
-assert.rejects(runInWorker(moduleString, options), cjsLoadingESMError);
-runInWorker(cjsString, options); // does not reject
+{
+  const options = { eval: true, type: 'classic' };
+  assert.rejects(runInWorker(moduleString, options), cjsLoadingESMError);
+  runInWorker(cjsString, options); // does not reject
+}
 
-options = { eval: true, type: 'classic' };
-assert.rejects(runInWorker(moduleString, options), cjsLoadingESMError);
-runInWorker(cjsString, options); // does not reject
+{
+  const options = { eval: true, type: 'module' };
+  runInWorker(moduleString, options); // does not reject
+  assert.rejects(runInWorker(cjsString, options), esmLoadingCJSError);
+}
 
-options = { eval: true, type: 'module' };
-runInWorker(moduleString, options); // does not reject
-assert.rejects(runInWorker(cjsString, options), esmLoadingCJSError);
+{
+  const options = { eval: false, type: 'module' };
+  runInWorker(new URL(`data:text/javascript,${moduleString}`),
+              options); // does not reject
+  assert.rejects(runInWorker(new URL(`data:text/javascript,${cjsString}`),
+                             options), esmLoadingCJSError);
+}
 
-options = { eval: true, type: 'wasm' };
-assert.rejects(runInWorker(moduleString, options), invalidValueError);
-assert.rejects(runInWorker(cjsString, options), invalidValueError);
+{
+  const options = { eval: true, type: 'wasm' };
+  assert.rejects(runInWorker(moduleString, options), invalidValueError);
+  assert.rejects(runInWorker(cjsString, options), invalidValueError);
+}
+
+{
+  const options = { type: 'classic' };
+  assert.rejects(runInWorker(new URL(`data:text/javascript,${moduleString}`),
+                             options), invalidValueError2);
+  assert.rejects(runInWorker(new URL(`data:text/javascript,${cjsString}`),
+                             options), invalidValueError2);
+}

test/parallel/test-worker-unsupported-path.js

@@ -47,6 +47,4 @@ const { Worker } = require('worker_threads');
   };
   assert.throws(() => { new Worker(new URL('https://www.url.com')); },
                 expectedErr);
-  assert.throws(() => { new Worker(new URL('data:application/javascript,')); },
-                expectedErr);
 }