Refactor: pull out editor worker

edit/editor-worker-body.js

@@ -0,0 +1,77 @@
+/* global importScripts parseMozFormat parserlib CSSLint */
+'use strict';
+
+const loadScript = createLoadScript();
+const loadParserLib = createLoadParserLib();
+
+createAPI({
+  csslint: (code, config) => {
+    loadParserLib();
+    loadScript(['/vendor-overwrites/csslint/csslint.js']);
+    return CSSLint.verify(code, config).messages
+      .map(m => Object.assign(m, {rule: {id: m.rule.id}}));
+  },
+  stylelint: () => {
+
+  },
+  parseMozFormat: data => {
+    loadParserLib();
+    loadScript(['/js/moz-parser.js']);
+    return parseMozFormat(data);
+  }
+});
+
+function createLoadParserLib() {
+  let loaded = false;
+  return () => {
+    if (loaded) {
+      return;
+    }
+    importScripts('/vendor-overwrites/csslint/parserlib.js');
+    parserlib.css.Tokens[parserlib.css.Tokens.COMMENT].hide = false;
+    loaded = true;
+  };
+}
+
+function createLoadScript() {
+  const loaded = new Set();
+  return urls => {
+    urls = urls.filter(u => !loaded.has(u));
+    importScripts(...urls);
+    urls.forEach(u => loaded.add(u));
+  };
+}
+
+function createAPI(methods) {
+  self.onmessage = e => {
+    const message = e.data;
+    Promise.resolve()
+      .then(() => methods[message.action](...message.args))
+      .then(result =>
+        ({
+          requestId: message.requestId,
+          error: false,
+          data: result
+        })
+      )
+      .catch(err =>
+        ({
+          requestId: message.requestId,
+          error: true,
+          data: cloneError(err)
+        })
+      )
+      .then(data => self.postMessage(data));
+  };
+}
+
+function cloneError(err) {
+  return Object.assign({
+    name: err.name,
+    stack: err.stack,
+    message: err.message,
+    lineNumber: err.lineNumber,
+    columnNumber: err.columnNumber,
+    fileName: err.fileName
+  }, err);
+}

edit/editor-worker.js

@@ -0,0 +1,47 @@
+'use strict';
+
+var editorWorker = (() => { // eslint-disable-line no-var
+  let worker;
+  return createAPI(['csslint', 'stylelint', 'parseMozFormat']);
+
+  function createAPI(keys) {
+    const output = {};
+    for (const key of keys) {
+      output[key] = (...args) => {
+        if (!worker) {
+          worker = createWorker();
+        }
+        return worker.invoke(key, args);
+      };
+    }
+    return output;
+  }
+
+  function createWorker() {
+    let requestId = 0;
+    const pending = new Map();
+    const worker = new Worker('/edit/editor-worker-body.js');
+    worker.onmessage = e => {
+      const message = e.data;
+      if (message.error) {
+        pending.get(message.requestId).reject(message.data);
+      } else {
+        pending.get(message.requestId).resolve(message.data);
+      }
+      pending.delete(message.requestId);
+    };
+    return {invoke};
+
+    function invoke(action, args) {
+      return new Promise((resolve, reject) => {
+        pending.set(requestId, {resolve, reject});
+        worker.postMessage({
+          requestId,
+          action,
+          args
+        });
+        requestId++;
+      });
+    }
+  }
+})();