refactor: use async/await syntax (mozilla#411)

* refactor: enabled babel runtime in babel config.

* refactor: ported cmd/build.js to async/await syntax.

* refactor: ported cmd/run.js to asyn/await syntax.

* refactor: ported cmd/sign.js to async/await syntax.

* refactor: ported firefox/index.js to async/await syntax.

* refactor: ported firefox/remote.js to async/await syntax.

* refactor: ported util/artifacts.js to async/await syntax.

* refactor: ported util/manifest.js to async/await syntax.

* refactor: ported program.js to async/await syntax.

* test: added test case for the new isErrorWithCode helper.

* test: added no-multi-spaces eslint rule, and fixed related lint errors

* test: added eslint-plugin-async-await plugin and rules

* refactor: removed promisedStream var from defaultPackageCreator.

* refactor: rewrote establishConnection helper using a for loop and a custom range generator.

* style: changed a multiline string into a single line.

* style: tweaked try/catch blocks in cmd/sign and firefox/index modules.

* test: enabled require-yield eslint rule to enforce await usage in an async function.

* refactor: change non-reassigned identifier to const in src/program.

* refactor: revert generator usage in for loop.

* style: remove extra space in a log message printed to console.

Author: rpl

.babelrc

@@ -4,5 +4,11 @@
     "transform-flow-strip-types",
     "transform-class-properties",
     "transform-es2015-modules-commonjs",
+    [
+      "transform-runtime", {
+        "polyfill": false,
+        "regenerator": true
+      }
+    ]
   ]
 }

.eslintrc

@@ -1,6 +1,7 @@
 {
   "parser": "babel-eslint",
   "plugins": [
+    "async-await",
     "flowtype"
   ],
   "settings": {
@@ -62,6 +63,7 @@
     "no-loop-func": 0,
     "no-mixed-spaces-and-tabs": 2,
     "no-multi-str": 2,
+    "no-multi-spaces": 2,
     "no-multiple-empty-lines": [2, {"max": 2}],
     "no-new": 2,
     "no-plusplus": 0,
@@ -78,6 +80,7 @@
     "prefer-template": 2,
     "quote-props": [1, "consistent-as-needed"],
     "quotes": [2, "single", "avoid-escape"],
+    "require-yield": 2,
     "semi": [2, "always"],
     "space-before-blocks": [2, "always"],
     "space-before-function-paren": [2, "never"],
@@ -86,6 +89,9 @@
     "valid-typeof": 2,
     "wrap-iife": [2, "inside"],
 
+    "async-await/space-after-async": 2,
+    "async-await/space-after-await": 2,
+
     "flowtype/define-flow-type": 1,
     "flowtype/use-flow-type": 1,
     "flowtype/space-after-type-colon": [1, "always"]

package.json

@@ -71,13 +71,16 @@
     "babel-plugin-transform-es2015-modules-commonjs": "6.14.0",
     "babel-plugin-transform-flow-strip-types": "6.14.0",
     "babel-preset-es2015": "6.14.0",
+    "babel-plugin-transform-runtime": "6.15.0",
     "babel-preset-stage-2": "6.13.0",
+    "babel-runtime": "6.11.6",
     "chai": "3.5.0",
     "conventional-changelog-cli": "1.2.0",
     "conventional-changelog-lint": "1.0.1",
     "copy-dir": "0.3.0",
     "coveralls": "2.11.13",
     "deepcopy": "0.6.3",
+    "eslint-plugin-async-await": "0.0.0",
     "eslint-plugin-flowtype": "2.18.1",
     "firefox-client": "0.3.0",
     "flow-bin": "0.32.0",

src/cmd/build.js

@@ -40,41 +40,33 @@ export type PackageCreatorParams = {
 export type PackageCreatorFn =
     (params: PackageCreatorParams) => Promise<ExtensionBuildResult>;
 
-function defaultPackageCreator(
+async function defaultPackageCreator(
   {manifestData, sourceDir, fileFilter, artifactsDir}: PackageCreatorParams
 ): Promise<ExtensionBuildResult> {
+  let id;
 
-  return new Promise(
-    (resolve) => {
-      if (manifestData) {
-        const id = getManifestId(manifestData);
-        log.debug(`Using manifest id=${id || '[not specified]'}`);
-        resolve(manifestData);
-      } else {
-        resolve(getValidatedManifest(sourceDir));
-      }
-    })
-    .then((manifestData) => {
-      return zipDir(
-        sourceDir, {
-          filter: (...args) => fileFilter.wantFile(...args),
-        })
-        .then((buffer) => {
-          let packageName = safeFileName(
-            `${manifestData.name}-${manifestData.version}.zip`);
-          let extensionPath = path.join(artifactsDir, packageName);
-          let stream = createWriteStream(extensionPath);
-          let promisedStream = streamToPromise(stream);
-
-          stream.write(buffer, () => stream.end());
-
-          return promisedStream
-            .then(() => {
-              log.info(`Your web extension is ready: ${extensionPath}`);
-              return {extensionPath};
-            });
-        });
-    });
+  if (manifestData) {
+    id = getManifestId(manifestData);
+    log.debug(`Using manifest id=${id || '[not specified]'}`);
+  } else {
+    manifestData = await getValidatedManifest(sourceDir);
+  }
+
+  let buffer = await zipDir(sourceDir, {
+    filter: (...args) => fileFilter.wantFile(...args),
+  });
+
+  let packageName = safeFileName(
+    `${manifestData.name}-${manifestData.version}.zip`);
+  let extensionPath = path.join(artifactsDir, packageName);
+  let stream = createWriteStream(extensionPath);
+
+  stream.write(buffer, () => stream.end());
+
+  await streamToPromise(stream);
+
+  log.info(`Your web extension is ready: ${extensionPath}`);
+  return {extensionPath};
 }
 
 
@@ -93,7 +85,7 @@ export type BuildCmdOptions = {
   packageCreator?: PackageCreatorFn,
 };
 
-export default function build(
+export default async function build(
   {sourceDir, artifactsDir, asNeeded = false}: BuildCmdParams,
   {
     manifestData, fileFilter = new FileFilter(),
@@ -108,24 +100,24 @@ export default function build(
     manifestData, sourceDir, fileFilter, artifactsDir,
   });
 
-  return prepareArtifactsDir(artifactsDir)
-    .then(() => createPackage())
-    .then((result) => {
-      if (rebuildAsNeeded) {
-        log.info('Rebuilding when files change...');
-        onSourceChange({
-          sourceDir, artifactsDir,
-          onChange: () => {
-            return createPackage().catch((error) => {
-              log.error(error.stack);
-              throw error;
-            });
-          },
-          shouldWatchFile: (...args) => fileFilter.wantFile(...args),
+  await prepareArtifactsDir(artifactsDir);
+  let result = await createPackage();
+
+  if (rebuildAsNeeded) {
+    log.info('Rebuilding when files change...');
+    onSourceChange({
+      sourceDir, artifactsDir,
+      onChange: () => {
+        return createPackage().catch((error) => {
+          log.error(error.stack);
+          throw error;
         });
-      }
-      return result;
+      },
+      shouldWatchFile: (...args) => fileFilter.wantFile(...args),
     });
+  }
+
+  return result;
 }