test: fix RegExp nits

* Remove needless RegExp flag

  In fixed case, `/g` flag is needless in the boolean context.

* Remove needless RegExp capturing

  Use non-capturing grouping or remove capturing completely when:

  * capturing is useless per se, e.g. in test() check;
  * captured groups are not used afterward at all;
  * some of the later captured groups are not used afterward.

* Use test, not match/exec in boolean context

  match() and exec() return a complicated object,
  unneeded in a boolean context.

* Do not needlessly repeat RegExp creation

  This commit takes RegExp creation out of cycles and other repetitions.

  As long as the RegExp does not use /g flag and match indices,
  we are safe here.

  In tests, this fix hardly gives a significant performance gain,
  but it increases clarity and maintainability,
  reassuring some RegExps to be identical.

  RegExp in functions are not taken out of their functions:
  while these functions are called many times
  and their RegExps are recreated with each call,
  the performance gain in test cases
  does not seem to be worth decreasing function self-dependency.

PR-URL: #13770
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/common/index.js

@@ -267,8 +267,9 @@ if (exports.isWindows) {
 }
 
 const ifaces = os.networkInterfaces();
+const re = /lo/;
 exports.hasIPv6 = Object.keys(ifaces).some(function(name) {
-  return /lo/.test(name) && ifaces[name].some(function(info) {
+  return re.test(name) && ifaces[name].some(function(info) {
     return info.family === 'IPv6';
   });
 });
@@ -433,7 +434,7 @@ function leakedGlobals() {
       leaked.push(val);
 
   if (global.__coverage__) {
-    return leaked.filter((varname) => !/^(cov_|__cov)/.test(varname));
+    return leaked.filter((varname) => !/^(?:cov_|__cov)/.test(varname));
   } else {
     return leaked;
   }

test/debugger/helper-debugger-repl.js

@@ -51,12 +51,12 @@ function startDebugger(scriptToDebug) {
   child.stderr.pipe(process.stderr);
 
   child.on('line', function(line) {
-    line = line.replace(/^(debug> *)+/, '');
+    line = line.replace(/^(?:debug> *)+/, '');
     console.log(line);
     assert.ok(expected.length > 0, `Got unexpected line: ${line}`);
 
     const expectedLine = expected[0].lines.shift();
-    assert.ok(line.match(expectedLine) !== null, `${line} != ${expectedLine}`);
+    assert.ok(expectedLine.test(line), `${line} != ${expectedLine}`);
 
     if (expected[0].lines.length === 0) {
       const callback = expected[0].callback;

test/doctool/test-doctool-html.js

@@ -91,9 +91,11 @@ const testData = [
   },
 ];
 
+const spaces = /\s/g;
+
 testData.forEach((item) => {
   // Normalize expected data by stripping whitespace
-  const expected = item.html.replace(/\s/g, '');
+  const expected = item.html.replace(spaces, '');
   const includeAnalytics = typeof item.analyticsId !== 'undefined';
 
   fs.readFile(item.file, 'utf8', common.mustCall((err, input) => {
@@ -112,7 +114,7 @@ testData.forEach((item) => {
         common.mustCall((err, output) => {
           assert.ifError(err);
 
-          const actual = output.replace(/\s/g, '');
+          const actual = output.replace(spaces, '');
           // Assert that the input stripped of all whitespace contains the
           // expected list
           assert.notStrictEqual(actual.indexOf(expected), -1);

test/inspector/inspector-helper.js

@@ -521,11 +521,11 @@ exports.startNodeForInspectorTest = function(callback,
     clearTimeout(timeoutId);
     console.log('[err]', text);
     if (found) return;
-    const match = text.match(/Debugger listening on ws:\/\/(.+):(\d+)\/(.+)/);
+    const match = text.match(/Debugger listening on ws:\/\/.+:(\d+)\/.+/);
     found = true;
     child.stderr.removeListener('data', dataCallback);
     assert.ok(match, text);
-    callback(new Harness(match[2], child));
+    callback(new Harness(match[1], child));
   });
 
   child.stderr.on('data', dataCallback);

test/inspector/test-inspector.js

@@ -13,8 +13,8 @@ function checkListResponse(err, response) {
   assert.strictEqual(1, response.length);
   assert.ok(response[0]['devtoolsFrontendUrl']);
   assert.ok(
-    response[0]['webSocketDebuggerUrl']
-      .match(/ws:\/\/127\.0\.0\.1:\d+\/[0-9A-Fa-f]{8}-/));
+    /ws:\/\/127\.0\.0\.1:\d+\/[0-9A-Fa-f]{8}-/
+      .test(response[0]['webSocketDebuggerUrl']));
 }
 
 function checkVersion(err, response) {

test/parallel/test-assert-checktag.js

@@ -7,10 +7,11 @@ const util = require('util');
 // for assert.throws()
 function re(literals, ...values) {
   let result = literals[0];
+  const escapeRE = /[\\^$.*+?()[\]{}|=!<>:-]/g;
   for (const [i, value] of values.entries()) {
     const str = util.inspect(value);
     // Need to escape special characters.
-    result += str.replace(/[\\^$.*+?()[\]{}|=!<>:-]/g, '\\$&');
+    result += str.replace(escapeRE, '\\$&');
     result += literals[i + 1];
   }
   return common.expectsError({

test/parallel/test-assert-deep.js

@@ -7,10 +7,11 @@ const util = require('util');
 // for assert.throws()
 function re(literals, ...values) {
   let result = literals[0];
+  const escapeRE = /[\\^$.*+?()[\]{}|=!<>:-]/g;
   for (const [i, value] of values.entries()) {
     const str = util.inspect(value);
     // Need to escape special characters.
-    result += str.replace(/[\\^$.*+?()[\]{}|=!<>:-]/g, '\\$&');
+    result += str.replace(escapeRE, '\\$&');
     result += literals[i + 1];
   }
   return common.expectsError({

test/parallel/test-assert.js

@@ -722,13 +722,14 @@ assert.throws(() => {
 {
   // bad args to AssertionError constructor should throw TypeError
   const args = [1, true, false, '', null, Infinity, Symbol('test'), undefined];
+  const re = /^The "options" argument must be of type object$/;
   args.forEach((input) => {
     assert.throws(
       () => new assert.AssertionError(input),
       common.expectsError({
         code: 'ERR_INVALID_ARG_TYPE',
         type: TypeError,
-        message: /^The "options" argument must be of type object$/
+        message: re
       }));
   });
 }

test/parallel/test-buffer-bytelength.js

@@ -7,14 +7,11 @@ const SlowBuffer = require('buffer').SlowBuffer;
 const vm = require('vm');
 
 // coerce values to string
-assert.throws(() => { Buffer.byteLength(32, 'latin1'); },
-              /"string" must be a string, Buffer, or ArrayBuffer/);
-assert.throws(() => { Buffer.byteLength(NaN, 'utf8'); },
-              /"string" must be a string, Buffer, or ArrayBuffer/);
-assert.throws(() => { Buffer.byteLength({}, 'latin1'); },
-              /"string" must be a string, Buffer, or ArrayBuffer/);
-assert.throws(() => { Buffer.byteLength(); },
-              /"string" must be a string, Buffer, or ArrayBuffer/);
+const re = /"string" must be a string, Buffer, or ArrayBuffer/;
+assert.throws(() => { Buffer.byteLength(32, 'latin1'); }, re);
+assert.throws(() => { Buffer.byteLength(NaN, 'utf8'); }, re);
+assert.throws(() => { Buffer.byteLength({}, 'latin1'); }, re);
+assert.throws(() => { Buffer.byteLength(); }, re);
 
 assert.strictEqual(Buffer.byteLength('', undefined, true), -1);
 

test/parallel/test-buffer-prototype-inspect.js

@@ -19,5 +19,5 @@ const util = require('util');
 
 {
   const buf = Buffer.from('x'.repeat(51));
-  assert.ok(/^<Buffer (78 ){50}\.\.\. >$/.test(util.inspect(buf)));
+  assert.ok(/^<Buffer (?:78 ){50}\.\.\. >$/.test(util.inspect(buf)));
 }

test/parallel/test-child-process-constructor.js

@@ -8,44 +8,48 @@ assert.strictEqual(typeof ChildProcess, 'function');
 {
   // Verify that invalid options to spawn() throw.
   const child = new ChildProcess();
+  const re = /^TypeError: "options" must be an object$/;
 
   [undefined, null, 'foo', 0, 1, NaN, true, false].forEach((options) => {
     assert.throws(() => {
       child.spawn(options);
-    }, /^TypeError: "options" must be an object$/);
+    }, re);
   });
 }
 
 {
   // Verify that spawn throws if file is not a string.
   const child = new ChildProcess();
+  const re = /^TypeError: "file" must be a string$/;
 
   [undefined, null, 0, 1, NaN, true, false, {}].forEach((file) => {
     assert.throws(() => {
       child.spawn({ file });
-    }, /^TypeError: "file" must be a string$/);
+    }, re);
   });
 }
 
 {
   // Verify that spawn throws if envPairs is not an array or undefined.
   const child = new ChildProcess();
+  const re = /^TypeError: "envPairs" must be an array$/;
 
   [null, 0, 1, NaN, true, false, {}, 'foo'].forEach((envPairs) => {
     assert.throws(() => {
       child.spawn({ envPairs, stdio: ['ignore', 'ignore', 'ignore', 'ipc'] });
-    }, /^TypeError: "envPairs" must be an array$/);
+    }, re);
   });
 }
 
 {
   // Verify that spawn throws if args is not an array or undefined.
   const child = new ChildProcess();
+  const re = /^TypeError: "args" must be an array$/;
 
   [null, 0, 1, NaN, true, false, {}, 'foo'].forEach((args) => {
     assert.throws(() => {
       child.spawn({ file: 'foo', args });
-    }, /^TypeError: "args" must be an array$/);
+    }, re);
   });
 }
 

test/parallel/test-cli-syntax.js

@@ -13,6 +13,9 @@ const syntaxArgs = [
   ['--check']
 ];
 
+const syntaxErrorRE = /^SyntaxError: Unexpected identifier$/m;
+const notFoundRE = /^Error: Cannot find module/m;
+
 // test good syntax with and without shebang
 [
   'syntax/good_syntax.js',
@@ -56,8 +59,7 @@ const syntaxArgs = [
     assert(c.stderr.startsWith(file), "stderr doesn't start with the filename");
 
     // stderr should have a syntax error message
-    const match = c.stderr.match(/^SyntaxError: Unexpected identifier$/m);
-    assert(match, 'stderr incorrect');
+    assert(syntaxErrorRE.test(c.stderr), 'stderr incorrect');
 
     assert.strictEqual(c.status, 1, `code === ${c.status}`);
   });
@@ -79,8 +81,7 @@ const syntaxArgs = [
     assert.strictEqual(c.stdout, '', 'stdout produced');
 
     // stderr should have a module not found error message
-    const match = c.stderr.match(/^Error: Cannot find module/m);
-    assert(match, 'stderr incorrect');
+    assert(notFoundRE.test(c.stderr), 'stderr incorrect');
 
     assert.strictEqual(c.status, 1, `code === ${c.status}`);
   });
@@ -112,8 +113,7 @@ syntaxArgs.forEach(function(args) {
   assert.strictEqual(c.stdout, '', 'stdout produced');
 
   // stderr should have a syntax error message
-  const match = c.stderr.match(/^SyntaxError: Unexpected identifier$/m);
-  assert(match, 'stderr incorrect');
+  assert(syntaxErrorRE.test(c.stderr), 'stderr incorrect');
 
   assert.strictEqual(c.status, 1, `code === ${c.status}`);
 });

test/parallel/test-crypto-authenticated.js

@@ -328,6 +328,13 @@ const TEST_CASES = [
     tag: 'a44a8266ee1c8eb0c8b5d4cf5ae9f19a', tampered: false },
 ];
 
+const errMessages = {
+  auth: / auth/,
+  state: / state/,
+  FIPS: /not supported in FIPS mode/,
+  length: /Invalid IV length/,
+};
+
 const ciphers = crypto.getCiphers();
 
 for (const i in TEST_CASES) {
@@ -378,14 +385,14 @@ for (const i in TEST_CASES) {
       assert.strictEqual(msg, test.plain);
     } else {
       // assert that final throws if input data could not be verified!
-      assert.throws(function() { decrypt.final('ascii'); }, / auth/);
+      assert.throws(function() { decrypt.final('ascii'); }, errMessages.auth);
     }
   }
 
   if (test.password) {
     if (common.hasFipsCrypto) {
       assert.throws(() => { crypto.createCipher(test.algo, test.password); },
-                    /not supported in FIPS mode/);
+                    errMessages.FIPS);
     } else {
       const encrypt = crypto.createCipher(test.algo, test.password);
       if (test.aad)
@@ -404,7 +411,7 @@ for (const i in TEST_CASES) {
   if (test.password) {
     if (common.hasFipsCrypto) {
       assert.throws(() => { crypto.createDecipher(test.algo, test.password); },
-                    /not supported in FIPS mode/);
+                    errMessages.FIPS);
     } else {
       const decrypt = crypto.createDecipher(test.algo, test.password);
       decrypt.setAuthTag(Buffer.from(test.tag, 'hex'));
@@ -416,7 +423,7 @@ for (const i in TEST_CASES) {
         assert.strictEqual(msg, test.plain);
       } else {
         // assert that final throws if input data could not be verified!
-        assert.throws(function() { decrypt.final('ascii'); }, / auth/);
+        assert.throws(function() { decrypt.final('ascii'); }, errMessages.auth);
       }
     }
   }
@@ -427,7 +434,7 @@ for (const i in TEST_CASES) {
                                           Buffer.from(test.key, 'hex'),
                                           Buffer.from(test.iv, 'hex'));
     encrypt.update('blah', 'ascii');
-    assert.throws(function() { encrypt.getAuthTag(); }, / state/);
+    assert.throws(function() { encrypt.getAuthTag(); }, errMessages.state);
   }
 
   {
@@ -436,15 +443,15 @@ for (const i in TEST_CASES) {
                                           Buffer.from(test.key, 'hex'),
                                           Buffer.from(test.iv, 'hex'));
     assert.throws(() => { encrypt.setAuthTag(Buffer.from(test.tag, 'hex')); },
-                  / state/);
+                  errMessages.state);
   }
 
   {
     // trying to read tag from decryption object:
     const decrypt = crypto.createDecipheriv(test.algo,
                                             Buffer.from(test.key, 'hex'),
                                             Buffer.from(test.iv, 'hex'));
-    assert.throws(function() { decrypt.getAuthTag(); }, / state/);
+    assert.throws(function() { decrypt.getAuthTag(); }, errMessages.state);
   }
 
   {
@@ -455,7 +462,7 @@ for (const i in TEST_CASES) {
         Buffer.from(test.key, 'hex'),
         Buffer.alloc(0)
       );
-    }, /Invalid IV length/);
+    }, errMessages.length);
   }
 }
 
@@ -467,6 +474,7 @@ for (const i in TEST_CASES) {
                             '6fKjEjR3Vl30EUYC');
   encrypt.update('blah', 'ascii');
   encrypt.final();
-  assert.throws(() => encrypt.getAuthTag(), / state/);
-  assert.throws(() => encrypt.setAAD(Buffer.from('123', 'ascii')), / state/);
+  assert.throws(() => encrypt.getAuthTag(), errMessages.state);
+  assert.throws(() => encrypt.setAAD(Buffer.from('123', 'ascii')),
+                errMessages.state);
 }

test/parallel/test-crypto-cipheriv-decipheriv.js

@@ -66,12 +66,14 @@ testCipher2(Buffer.from('0123456789abcd0123456789'), Buffer.from('12345678'));
 // Zero-sized IV should be accepted in ECB mode.
 crypto.createCipheriv('aes-128-ecb', Buffer.alloc(16), Buffer.alloc(0));
 
+const errMessage = /Invalid IV length/;
+
 // But non-empty IVs should be rejected.
 for (let n = 1; n < 256; n += 1) {
   assert.throws(
       () => crypto.createCipheriv('aes-128-ecb', Buffer.alloc(16),
                                   Buffer.alloc(n)),
-      /Invalid IV length/);
+      errMessage);
 }
 
 // Correctly sized IV should be accepted in CBC mode.
@@ -83,14 +85,14 @@ for (let n = 0; n < 256; n += 1) {
   assert.throws(
       () => crypto.createCipheriv('aes-128-cbc', Buffer.alloc(16),
                                   Buffer.alloc(n)),
-      /Invalid IV length/);
+      errMessage);
 }
 
 // Zero-sized IV should be rejected in GCM mode.
 assert.throws(
     () => crypto.createCipheriv('aes-128-gcm', Buffer.alloc(16),
                                 Buffer.alloc(0)),
-    /Invalid IV length/);
+    errMessage);
 
 // But all other IV lengths should be accepted.
 for (let n = 1; n < 256; n += 1) {

test/parallel/test-crypto-dh.js

@@ -295,14 +295,15 @@ if (availableCurves.has('prime256v1') && availableCurves.has('secp256k1')) {
   // rejected.
   ecdh5.setPrivateKey(cafebabeKey, 'hex');
 
-  [ // Some invalid private keys for the secp256k1 curve.
-    '0000000000000000000000000000000000000000000000000000000000000000',
-    'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141',
-    'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF',
+  // Some invalid private keys for the secp256k1 curve.
+  const errMessage = /^Error: Private key is not valid for specified curve\.$/;
+  ['0000000000000000000000000000000000000000000000000000000000000000',
+   'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141',
+   'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF',
   ].forEach((element) => {
     assert.throws(() => {
       ecdh5.setPrivateKey(element, 'hex');
-    }, /^Error: Private key is not valid for specified curve\.$/);
+    }, errMessage);
     // Verify object state did not change.
     assert.strictEqual(ecdh5.getPrivateKey('hex'), cafebabeKey);
   });