[v12.x backport] tools: enable no-else-return lint rule

.eslintrc.js

@@ -129,6 +129,7 @@ module.exports = {
     'no-dupe-else-if': 'error',
     'no-duplicate-case': 'error',
     'no-duplicate-imports': 'error',
+    'no-else-return': ['error', { allowElseIf: true }],
     'no-empty-character-class': 'error',
     'no-ex-assign': 'error',
     'no-extra-boolean-cast': 'error',

benchmark/es/spread-bench.js

@@ -16,11 +16,10 @@ function makeTest(count, rest) {
     return function test(...args) {
       assert.strictEqual(count, args.length);
     };
-  } else {
-    return function test() {
-      assert.strictEqual(count, arguments.length);
-    };
   }
+  return function test() {
+    assert.strictEqual(count, arguments.length);
+  };
 }
 
 function main({ n, context, count, rest, method }) {

benchmark/scatter.js

@@ -30,9 +30,8 @@ let printHeader = true;
 function csvEncodeValue(value) {
   if (typeof value === 'number') {
     return value.toString();
-  } else {
-    return `"${value.replace(/"/g, '""')}"`;
   }
+  return `"${value.replace(/"/g, '""')}"`;
 }
 
 (function recursive(i) {

lib/_http_incoming.js

@@ -239,9 +239,8 @@ function matchKnownFields(field, lowercased) {
   }
   if (lowercased) {
     return '\u0000' + field;
-  } else {
-    return matchKnownFields(field.toLowerCase(), true);
   }
+  return matchKnownFields(field.toLowerCase(), true);
 }
 // Add the given (field, value) pair to the message
 //

lib/_stream_readable.js

@@ -365,8 +365,7 @@ function howMuchToRead(n, state) {
     // Only flow one buffer at a time
     if (state.flowing && state.length)
       return state.buffer.first().length;
-    else
-      return state.length;
+    return state.length;
   }
   if (n <= state.length)
     return n;

lib/_tls_wrap.js

@@ -1518,12 +1518,11 @@ function onConnectSecure() {
     if (options.rejectUnauthorized) {
       this.destroy(verifyError);
       return;
-    } else {
-      debug('client emit secureConnect. rejectUnauthorized: %s, ' +
-            'authorizationError: %s', options.rejectUnauthorized,
-            this.authorizationError);
-      this.emit('secureConnect');
     }
+    debug('client emit secureConnect. rejectUnauthorized: %s, ' +
+          'authorizationError: %s', options.rejectUnauthorized,
+          this.authorizationError);
+    this.emit('secureConnect');
   } else {
     this.authorized = true;
     debug('client emit secureConnect. authorized:', this.authorized);

lib/dns.js

@@ -261,9 +261,8 @@ function resolve(hostname, rrtype, callback) {
 
   if (typeof resolver === 'function') {
     return resolver.call(this, hostname, callback);
-  } else {
-    throw new ERR_INVALID_OPT_VALUE('rrtype', rrtype);
   }
+  throw new ERR_INVALID_OPT_VALUE('rrtype', rrtype);
 }
 
 function defaultResolverSetServers(servers) {

lib/events.js

@@ -577,9 +577,8 @@ EventEmitter.prototype.rawListeners = function rawListeners(type) {
 EventEmitter.listenerCount = function(emitter, type) {
   if (typeof emitter.listenerCount === 'function') {
     return emitter.listenerCount(type);
-  } else {
-    return listenerCount.call(emitter, type);
   }
+  return listenerCount.call(emitter, type);
 };
 
 EventEmitter.prototype.listenerCount = listenerCount;

lib/fs.js

@@ -1511,9 +1511,8 @@ function encodeRealpathResult(result, options) {
   const asBuffer = Buffer.from(result);
   if (options.encoding === 'buffer') {
     return asBuffer;
-  } else {
-    return asBuffer.toString(options.encoding);
   }
+  return asBuffer.toString(options.encoding);
 }
 
 // Finds the next portion of a (partial) path, up to the next path delimiter

lib/internal/crypto/keys.js

@@ -277,14 +277,13 @@ function prepareAsymmetricKey(key, ctx) {
     const isPublic =
       (ctx === kConsumePrivate || ctx === kCreatePrivate) ? false : undefined;
     return { data, ...parseKeyEncoding(key, undefined, isPublic) };
-  } else {
-    throw new ERR_INVALID_ARG_TYPE(
-      'key',
-      ['string', 'Buffer', 'TypedArray', 'DataView',
-       ...(ctx !== kCreatePrivate ? ['KeyObject'] : [])],
-      key
-    );
   }
+  throw new ERR_INVALID_ARG_TYPE(
+    'key',
+    ['string', 'Buffer', 'TypedArray', 'DataView',
+     ...(ctx !== kCreatePrivate ? ['KeyObject'] : [])],
+    key
+  );
 }
 
 function preparePrivateKey(key) {
@@ -301,13 +300,12 @@ function prepareSecretKey(key, bufferOnly = false) {
       if (key.type !== 'secret')
         throw new ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE(key.type, 'secret');
       return key[kHandle];
-    } else {
-      throw new ERR_INVALID_ARG_TYPE(
-        'key',
-        ['Buffer', 'TypedArray', 'DataView',
-         ...(bufferOnly ? [] : ['string', 'KeyObject'])],
-        key);
     }
+    throw new ERR_INVALID_ARG_TYPE(
+      'key',
+      ['Buffer', 'TypedArray', 'DataView',
+       ...(bufferOnly ? [] : ['string', 'KeyObject'])],
+      key);
   }
   return key;
 }

lib/internal/crypto/sig.js

@@ -70,8 +70,7 @@ function getDSASignatureEncoding(options) {
       return kSigEncDER;
     else if (dsaEncoding === 'ieee-p1363')
       return kSigEncP1363;
-    else
-      throw new ERR_INVALID_OPT_VALUE('dsaEncoding', dsaEncoding);
+    throw new ERR_INVALID_OPT_VALUE('dsaEncoding', dsaEncoding);
   }
 
   return kSigEncDER;
@@ -82,9 +81,8 @@ function getIntOption(name, options) {
   if (value !== undefined) {
     if (value === value >> 0) {
       return value;
-    } else {
-      throw new ERR_INVALID_OPT_VALUE(name, value);
     }
+    throw new ERR_INVALID_OPT_VALUE(name, value);
   }
   return undefined;
 }

lib/internal/errors.js

@@ -1106,10 +1106,9 @@ E('ERR_INVALID_MODULE_SPECIFIER', (pkgPath, subpath, base = undefined) => {
     assert(subpath !== '.');
     return `Package subpath '${subpath}' is not a valid module request for ` +
       `the "exports" resolution of ${pkgPath}${sep}package.json`;
-  } else {
-    return `Package subpath '${subpath}' is not a valid module request for ` +
-      `the "exports" resolution of ${pkgPath} imported from ${base}`;
   }
+  return `Package subpath '${subpath}' is not a valid module request for ` +
+      `the "exports" resolution of ${pkgPath} imported from ${base}`;
 }, TypeError);
 E('ERR_INVALID_OPT_VALUE', (name, value) =>
   `The value "${String(value)}" is invalid for option "${name}"`,
@@ -1120,8 +1119,7 @@ E('ERR_INVALID_OPT_VALUE_ENCODING',
 E('ERR_INVALID_PACKAGE_CONFIG', (path, message, hasMessage = true) => {
   if (hasMessage)
     return `Invalid package config ${path}${sep}package.json, ${message}`;
-  else
-    return `Invalid JSON in ${path} imported from ${message}`;
+  return `Invalid JSON in ${path} imported from ${message}`;
 }, Error);
 E('ERR_INVALID_PACKAGE_TARGET',
   (pkgPath, key, subpath, target, base = undefined) => {
@@ -1132,11 +1130,10 @@ E('ERR_INVALID_PACKAGE_TARGET',
         return `Invalid "exports" target ${JSONStringify(target)} defined ` +
         `for '${subpath}' in the package config ${pkgPath} imported from ` +
         `${base}.${relError ? '; targets must start with "./"' : ''}`;
-      } else {
-        return `Invalid "exports" main target ${target} defined in the ` +
-          `package config ${pkgPath} imported from ${base}${relError ?
-            '; targets must start with "./"' : ''}`;
       }
+      return `Invalid "exports" main target ${target} defined in the ` +
+        `package config ${pkgPath} imported from ${base}${relError ?
+          '; targets must start with "./"' : ''}`;
     } else if (key === '.') {
       return `Invalid "exports" main target ${JSONStringify(target)} defined ` +
       `in the package config ${pkgPath}${sep}package.json${relError ?
@@ -1146,11 +1143,10 @@ E('ERR_INVALID_PACKAGE_TARGET',
         StringPrototypeSlice(key, 0, -subpath.length || key.length)}' in the ` +
         `package config ${pkgPath}${sep}package.json; ` +
         'targets must start with "./"';
-    } else {
-      return `Invalid "exports" target ${JSONStringify(target)} defined for '${
-        StringPrototypeSlice(key, 0, -subpath.length || key.length)}' in the ` +
-      `package config ${pkgPath}${sep}package.json`;
     }
+    return `Invalid "exports" target ${JSONStringify(target)} defined for '${
+      StringPrototypeSlice(key, 0, -subpath.length || key.length)}' in the ` +
+    `package config ${pkgPath}${sep}package.json`;
   }, Error);
 E('ERR_INVALID_PERFORMANCE_MARK',
   'The "%s" performance mark has not been set', Error);
@@ -1305,10 +1301,9 @@ E('ERR_PACKAGE_PATH_NOT_EXPORTED', (pkgPath, subpath, base = undefined) => {
   } else if (base === undefined) {
     return `Package subpath '${subpath}' is not defined by "exports" in ${
       pkgPath}${sep}package.json`;
-  } else {
-    return `Package subpath '${subpath}' is not defined by "exports" in ${
-      pkgPath} imported from ${base}`;
   }
+  return `Package subpath '${subpath}' is not defined by "exports" in ${
+    pkgPath} imported from ${base}`;
 }, Error);
 E('ERR_REQUIRE_ESM',
   (filename, parentPath = null, packageJsonPath = null) => {

lib/internal/fs/streams.js

@@ -452,9 +452,8 @@ WriteStream.prototype.close = function(cb) {
     if (this.closed) {
       process.nextTick(cb);
       return;
-    } else {
-      this.on('close', cb);
     }
+    this.on('close', cb);
   }
 
   // If we are not autoClosing, we should call

lib/internal/modules/esm/get_source.js

@@ -28,8 +28,7 @@ async function defaultGetSource(url, { format } = {}, defaultGetSource) {
     return {
       source: Buffer.from(body, base64 ? 'base64' : 'utf8')
     };
-  } else {
-    throw new ERR_INVALID_URL_SCHEME(['file', 'data']);
   }
+  throw new ERR_INVALID_URL_SCHEME(['file', 'data']);
 }
 exports.defaultGetSource = defaultGetSource;

lib/internal/modules/esm/resolve.js

@@ -430,10 +430,9 @@ function packageMainResolve(packageJSONUrl, packageConfig, base, conditions) {
       if (packageConfig.main !== undefined) {
         return finalizeResolution(
           new URL(packageConfig.main, packageJSONUrl), base);
-      } else {
-        return finalizeResolution(
-          new URL('index', packageJSONUrl), base);
       }
+      return finalizeResolution(
+        new URL('index', packageJSONUrl), base);
     }
     return legacyMainResolve(packageJSONUrl, packageConfig);
   }
@@ -553,10 +552,9 @@ function packageResolve(specifier, base, conditions) {
       } else if (packageSubpath === '') {
         return packageMainResolve(packageJSONUrl, packageConfig, base,
                                   conditions);
-      } else {
-        return packageExportsResolve(
-          packageJSONUrl, packageSubpath, packageConfig, base, conditions);
       }
+      return packageExportsResolve(
+        packageJSONUrl, packageSubpath, packageConfig, base, conditions);
     }
   }
 
@@ -585,10 +583,9 @@ function packageResolve(specifier, base, conditions) {
     } else if (packageConfig.exports !== undefined) {
       return packageExportsResolve(
         packageJSONUrl, packageSubpath, packageConfig, base, conditions);
-    } else {
-      return finalizeResolution(
-        new URL(packageSubpath, packageJSONUrl), base);
     }
+    return finalizeResolution(
+      new URL(packageSubpath, packageJSONUrl), base);
     // Cross-platform root check.
   } while (packageJSONPath.length !== lastPath.length);
 

lib/internal/policy/manifest.js

@@ -145,32 +145,31 @@ class Manifest {
         const dependencyRedirectList = (toSpecifier) => {
           if (toSpecifier in dependencyMap !== true) {
             return null;
-          } else {
-            const to = dependencyMap[toSpecifier];
-            if (to === true) {
-              return true;
-            }
-            if (parsedURLs.has(to)) {
-              return parsedURLs.get(to);
-            } else if (canBeRequiredByUsers(to)) {
-              const href = `node:${to}`;
-              const resolvedURL = new URL(href);
-              parsedURLs.set(to, resolvedURL);
-              parsedURLs.set(href, resolvedURL);
-              return resolvedURL;
-            } else if (RegExpPrototypeTest(kRelativeURLStringPattern, to)) {
-              const resolvedURL = new URL(to, manifestURL);
-              const href = resourceURL.href;
-              parsedURLs.set(to, resolvedURL);
-              parsedURLs.set(href, resolvedURL);
-              return resolvedURL;
-            }
-            const resolvedURL = new URL(to);
+          }
+          const to = dependencyMap[toSpecifier];
+          if (to === true) {
+            return true;
+          }
+          if (parsedURLs.has(to)) {
+            return parsedURLs.get(to);
+          } else if (canBeRequiredByUsers(to)) {
+            const href = `node:${to}`;
+            const resolvedURL = new URL(href);
+            parsedURLs.set(to, resolvedURL);
+            parsedURLs.set(href, resolvedURL);
+            return resolvedURL;
+          } else if (RegExpPrototypeTest(kRelativeURLStringPattern, to)) {
+            const resolvedURL = new URL(to, manifestURL);
             const href = resourceURL.href;
             parsedURLs.set(to, resolvedURL);
             parsedURLs.set(href, resolvedURL);
             return resolvedURL;
           }
+          const resolvedURL = new URL(to);
+          const href = resourceURL.href;
+          parsedURLs.set(to, resolvedURL);
+          parsedURLs.set(href, resolvedURL);
+          return resolvedURL;
         };
         dependencies.set(resourceHREF, dependencyRedirectList);
       } else if (dependencyMap === true) {

lib/internal/source_map/source_map.js

@@ -196,15 +196,14 @@ class SourceMap {
       return {};
     } else if (!entry) {
       return {};
-    } else {
-      return {
-        generatedLine: entry[0],
-        generatedColumn: entry[1],
-        originalSource: entry[2],
-        originalLine: entry[3],
-        originalColumn: entry[4]
-      };
     }
+    return {
+      generatedLine: entry[0],
+      generatedColumn: entry[1],
+      originalSource: entry[2],
+      originalLine: entry[3],
+      originalColumn: entry[4]
+    };
   }
 
   /**

lib/internal/source_map/source_map_cache.js

@@ -192,9 +192,8 @@ function sourceMapCacheToObject() {
 
   if (ObjectKeys(obj).length === 0) {
     return undefined;
-  } else {
-    return obj;
   }
+  return obj;
 }
 
 // Since WeakMap can't be iterated over, we use Module._cache's
@@ -243,9 +242,8 @@ function findSourceMap(uri, error) {
   }
   if (sourceMap && sourceMap.data) {
     return new SourceMap(sourceMap.data);
-  } else {
-    return undefined;
   }
+  return undefined;
 }
 
 module.exports = {