chore: Added prefer-const to eslint and related changes (#700)

.eslintrc

@@ -103,6 +103,7 @@
     }],
     "object-shorthand": 2,
     "one-var": [2, "never"],
+    "prefer-const": 2,
     "prefer-template": 2,
     "quote-props": [1, "consistent-as-needed"],
     "quotes": [2, "single", "avoid-escape"],

src/cmd/build.js

@@ -104,23 +104,23 @@ async function defaultPackageCreator({
     manifestData = await getValidatedManifest(sourceDir);
   }
 
-  let buffer = await zipDir(sourceDir, {
+  const buffer = await zipDir(sourceDir, {
     filter: (...args) => fileFilter.wantFile(...args),
   });
 
   let extensionName: string = manifestData.name;
 
   if (manifestData.default_locale) {
-    let messageFile = path.join(sourceDir, '_locales',
+    const messageFile = path.join(sourceDir, '_locales',
       manifestData.default_locale, 'messages.json');
     log.debug('Manifest declared default_locale, localizing extension name');
     extensionName = await getDefaultLocalizedName(
       {messageFile, manifestData});
   }
-  let packageName = safeFileName(
+  const packageName = safeFileName(
     `${extensionName}-${manifestData.version}.zip`);
-  let extensionPath = path.join(artifactsDir, packageName);
-  let stream = createWriteStream(extensionPath);
+  const extensionPath = path.join(artifactsDir, packageName);
+  const stream = createWriteStream(extensionPath);
 
   stream.write(buffer, () => stream.end());
 
@@ -166,7 +166,7 @@ export default async function build(
   });
 
   await prepareArtifactsDir(artifactsDir);
-  let result = await createPackage();
+  const result = await createPackage();
 
   if (rebuildAsNeeded) {
     log.info('Rebuilding when files change...');

src/cmd/run.js

@@ -82,14 +82,15 @@ export function defaultReloadStrategy(
     createWatcher = defaultWatcherCreator,
   }: ReloadStrategyOptions = {}
 ): void {
-  let watcher: Watchpack;
+  const watcher: Watchpack = (
+    createWatcher({addonId, client, sourceDir, artifactsDir})
+  );
 
   firefoxProcess.on('close', () => {
     client.disconnect();
     watcher.close();
   });
 
-  watcher = createWatcher({addonId, client, sourceDir, artifactsDir});
 }
 
 
@@ -181,15 +182,12 @@ export default async function run(
   const requiresRemote = !preInstall;
   let installed = false;
 
-  let runner;
-  let profile;
   let client;
-  let runningFirefox;
   let addonId;
 
-  let manifestData = await getValidatedManifest(sourceDir);
+  const manifestData = await getValidatedManifest(sourceDir);
 
-  runner = new ExtensionRunner({
+  const runner = new ExtensionRunner({
     sourceDir,
     firefoxApp,
     firefox,
@@ -198,7 +196,7 @@ export default async function run(
     customPrefs,
   });
 
-  profile = await runner.getProfile();
+  const profile = await runner.getProfile();
 
   if (!preInstall) {
     log.debug('Deferring extension installation until after ' +
@@ -209,7 +207,7 @@ export default async function run(
     installed = true;
   }
 
-  runningFirefox = await runner.run(profile);
+  const runningFirefox = await runner.run(profile);
 
   if (installed) {
     log.debug('Not installing as temporary add-on because the ' +

src/cmd/sign.js

@@ -65,7 +65,7 @@ export default function sign(
         manifestData = await getValidatedManifest(sourceDir);
       }
 
-      let [buildResult, idFromSourceDir] = await Promise.all([
+      const [buildResult, idFromSourceDir] = await Promise.all([
         build({sourceDir, artifactsDir: tmpDir.path()},
               {manifestData, showReadyMessage: false}),
         getIdFromSourceDir(sourceDir),
@@ -93,7 +93,7 @@ export default function sign(
         log.warn('No extension ID specified (it will be auto-generated)');
       }
 
-      let signingResult = await signAddon({
+      const signingResult = await signAddon({
         apiKey,
         apiSecret,
         apiUrlPrefix,
@@ -152,7 +152,7 @@ export async function getIdFromSourceDir(
     }
   });
 
-  let id = lines[0];
+  const id = lines[0];
   log.debug(`Found extension ID ${id} in ${filePath}`);
 
   if (!id) {

src/firefox/index.js

@@ -211,7 +211,7 @@ export function configureProfile(
 ): Promise<FirefoxProfile> {
   // Set default preferences. Some of these are required for the add-on to
   // operate, such as disabling signatures.
-  let prefs = getPrefs(app);
+  const prefs = getPrefs(app);
   Object.keys(prefs).forEach((pref) => {
     profile.setPreference(pref, prefs[pref]);
   });
@@ -283,8 +283,8 @@ export async function copyProfile(
   }: CopyProfileOptions = {},
 ): Promise<FirefoxProfile> {
 
-  let copy = promisify(FirefoxProfile.copy);
-  let copyByName = promisify(copyFromUserProfile);
+  const copy = promisify(FirefoxProfile.copy);
+  const copyByName = promisify(copyFromUserProfile);
 
   try {
     const dirExists = await isDirectory(profileDirectory);

src/firefox/preferences.js

@@ -127,14 +127,17 @@ export function getPrefs(
 export function coerceCLICustomPreference(
   cliPrefs: string | Array<string>
 ): FirefoxPreferences {
-  let customPrefs = {};
+  const customPrefs = {};
 
   if (!Array.isArray(cliPrefs)) {
     cliPrefs = [cliPrefs];
   }
 
-  for (let pref of cliPrefs) {
-    let [key, value] = pref.split('=');
+
+  for (const pref of cliPrefs) {
+    const prefsAry = pref.split('=');
+    const key = prefsAry[0];
+    let value = prefsAry[1];
 
     if (/[^\w{@}.-]/.test(key)) {
       throw new UsageError(`Invalid custom preference name: ${key}`);

src/firefox/remote.js

@@ -154,7 +154,7 @@ export class RemoteFirefox {
       const response = await this.addonRequest(addon, 'requestTypes');
 
       if (response.requestTypes.indexOf('reload') === -1) {
-        let supportedRequestTypes = JSON.stringify(response.requestTypes);
+        const supportedRequestTypes = JSON.stringify(response.requestTypes);
         log.debug(
           `Remote Firefox only supports: ${supportedRequestTypes}`);
         throw new UsageError(

src/program.js

@@ -98,7 +98,7 @@ export class Program {
     // Command line option (pref) renamed for internal use (customPref).
     argv.customPrefs = argv.pref;
 
-    let runCommand = this.commands[cmd];
+    const runCommand = this.commands[cmd];
 
     if (argv.verbose) {
       logStream.makeVerbose();
@@ -147,7 +147,7 @@ export function defaultVersionGetter(
 ): string {
   if (localEnv === 'production') {
     log.debug('Getting the version from package.json');
-    let packageData: any = readFileSync(
+    const packageData: any = readFileSync(
       path.join(absolutePackageDir, 'package.json'));
     return JSON.parse(packageData).version;
   } else {
@@ -164,7 +164,7 @@ export function main(
     runOptions = {},
   }: Object = {}
 ): Promise<any> {
-  let program = new Program(argv, {absolutePackageDir});
+  const program = new Program(argv, {absolutePackageDir});
   // yargs uses magic camel case expansion to expose options on the
   // final argv object. For example, the 'artifacts-dir' option is alternatively
   // available as argv.artifactsDir.

src/util/logger.js

@@ -84,7 +84,7 @@ export class ConsoleStream {
   }
 
   flushCapturedLogs({localProcess = process}: ConsoleOptions = {}) {
-    for (let msg of this.capturedMessages) {
+    for (const msg of this.capturedMessages) {
       localProcess.stdout.write(msg);
     }
     this.capturedMessages = [];

src/util/manifest.js

@@ -31,7 +31,7 @@ export type ExtensionManifest = {|
 export default async function getValidatedManifest(
   sourceDir: string
 ): Promise<ExtensionManifest> {
-  let manifestFile = path.join(sourceDir, 'manifest.json');
+  const manifestFile = path.join(sourceDir, 'manifest.json');
   log.debug(`Validating manifest at ${manifestFile}`);
 
   let manifestContents;
@@ -52,7 +52,7 @@ export default async function getValidatedManifest(
       `Error parsing manifest.json at ${manifestFile}: ${error}`);
   }
 
-  let errors = [];
+  const errors = [];
   // This is just some basic validation of what web-ext needs, not
   // what Firefox will need to run the extension.
   // TODO: integrate with the addons-linter for actual validation.

src/util/temp-dir.js

@@ -23,7 +23,7 @@ const log = createLogger(__filename);
  *
  */
 export function withTempDir(makePromise: Function): Promise<any> {
-  let tmpDir = new TempDir();
+  const tmpDir = new TempDir();
   return tmpDir.create()
     .then(() => {
       return makePromise(tmpDir);
@@ -62,15 +62,15 @@ export class TempDir {
    * been created.
    */
   create(): Promise<TempDir> {
-    let createTempDir = promisify(tmp.dir, {multiArgs: true});
+    const createTempDir = promisify(tmp.dir, {multiArgs: true});
     return createTempDir(
       {
         prefix: 'tmp-web-ext-',
         // This allows us to remove a non-empty tmp dir.
         unsafeCleanup: true,
       })
       .then((args) => {
-        let [tmpPath, removeTempDir] = args;
+        const [tmpPath, removeTempDir] = args;
         this._path = tmpPath;
         this._removeTempDir = removeTempDir;
         log.debug(`Created temporary directory: ${this.path()}`);

tests/functional/test.cli.lint.js

@@ -10,7 +10,7 @@ describe('web-ext lint', () => {
   it('should accept: --source-dir SRCDIR',
      () => withTempAddonDir({addonPath}, (srcDir, tmpDir) => {
        const argv = ['lint', '--source-dir', srcDir, '--verbose'];
-       let cmd = execCommand(webExt, argv, {cwd: tmpDir});
+       const cmd = execCommand(webExt, argv, {cwd: tmpDir});
 
        return cmd.waitForExit.then(({exitCode, stdout, stderr}) => {
          if (exitCode !== 0) {

tests/unit/helpers.js

@@ -148,11 +148,11 @@ export function fake<T>(original: Object, methods: Object = {}): T {
   }
 
   var proto = Object.getPrototypeOf(original);
-  for (let key of props) {
+  for (const key of props) {
     if (!original.hasOwnProperty(key) && !proto.hasOwnProperty(key)) {
       continue;
     }
-    let definition = original[key] || proto[key];
+    const definition = original[key] || proto[key];
     if (typeof definition === 'function') {
       stub[key] = () => {
         log.warn(`Running stubbed function ${key} (default implementation)`);

tests/unit/test-cmd/test.build.js

@@ -25,7 +25,7 @@ const log = createLogger(__filename);
 describe('build', () => {
 
   it('zips a package', () => {
-    let zipFile = new ZipFile();
+    const zipFile = new ZipFile();
 
     return withTempDir(
       (tmpDir) =>
@@ -201,8 +201,8 @@ describe('build', () => {
   ));
 
   it('asks FileFilter what files to include in the ZIP', () => {
-    let zipFile = new ZipFile();
-    let fileFilter = new FileFilter({
+    const zipFile = new ZipFile();
+    const fileFilter = new FileFilter({
       filesToIgnore: ['**/background-script.js'],
     });
 

tests/unit/test-cmd/test.run.js

@@ -32,12 +32,12 @@ describe('run', () => {
 
   function prepareRun(fakeInstallResult) {
     const sourceDir = fixturePath('minimal-web-ext');
-    let argv = {
+    const argv = {
       artifactsDir: path.join(sourceDir, 'web-ext-artifacts'),
       sourceDir,
       noReload: true,
     };
-    let options = {
+    const options = {
       firefoxApp: getFakeFirefox(),
       firefoxClient: sinon.spy(() => {
         return Promise.resolve(fake(RemoteFirefox.prototype, {
@@ -63,8 +63,8 @@ describe('run', () => {
   }
 
   function getFakeFirefox(implementations = {}) {
-    let profile = {}; // empty object just to avoid errors.
-    let allImplementations = {
+    const profile = {}; // empty object just to avoid errors.
+    const allImplementations = {
       createProfile: () => Promise.resolve(profile),
       copyProfile: () => Promise.resolve(profile),
       installExtension: () => Promise.resolve(),
@@ -76,7 +76,7 @@ describe('run', () => {
 
   it('installs and runs the extension', () => {
 
-    let profile = {};
+    const profile = {};
 
     const cmd = prepareRun();
     const {firefoxApp} = cmd.options;

tests/unit/test-cmd/test.sign.js

@@ -234,7 +234,7 @@ describe('sign', () => {
 
   it('returns a signing result', () => withTempDir(
     (tmpDir) => {
-      let stubs = getStubs();
+      const stubs = getStubs();
       return sign(tmpDir, stubs)
         .then((realResult) => {
           assert.deepEqual(realResult, stubs.signingResult);
@@ -267,7 +267,7 @@ describe('sign', () => {
       return sign(tmpDir, stubs, {extraArgs: {artifactsDir}})
         .then(() => {
           assert.equal(stubs.signAddon.called, true);
-          let signedAddonCall = stubs.signAddon.firstCall.args[0];
+          const signedAddonCall = stubs.signAddon.firstCall.args[0];
           assert.equal(signedAddonCall.apiKey,
                        stubs.signingConfig.apiKey);
           assert.equal(signedAddonCall.apiSecret,
@@ -294,7 +294,7 @@ describe('sign', () => {
 
   it('passes the verbose flag to the signer', () => withTempDir(
     (tmpDir) => {
-      let stubs = getStubs();
+      const stubs = getStubs();
       return sign(tmpDir, stubs, {extraArgs: {verbose: true}})
         .then(() => {
           assert.equal(stubs.signAddon.called, true);
@@ -305,7 +305,7 @@ describe('sign', () => {
 
   it('passes through a signing exception', () => withTempDir(
     (tmpDir) => {
-      let stubs = getStubs();
+      const stubs = getStubs();
       stubs.signAddon = () => Promise.reject(new Error('some signing error'));
 
       return sign(tmpDir, stubs)