benchmark: reduce string concatenations

PR-URL: https://github.com/nodejs/node/pull/12455
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

benchmark/_benchmark_progress.js

@@ -3,12 +3,13 @@
 const readline = require('readline');
 
 function pad(input, minLength, fill) {
-  var result = input + '';
+  var result = String(input);
-  return fill.repeat(Math.max(0, minLength - result.length)) + result;
+  var padding = fill.repeat(Math.max(0, minLength - result.length));
+  return `${padding}${result}`;
 }
 
 function fraction(numerator, denominator) {
-  const fdenominator = denominator + '';
+  const fdenominator = String(denominator);
   const fnumerator = pad(numerator, fdenominator.length, ' ');
   return `${fnumerator}/${fdenominator}`;
 }
@@ -100,11 +101,12 @@ class BenchmarkProgress {
     const percent = pad(Math.floor(completedRate * 100), 3, ' ');
 
     const caption = finished ? 'Done\n' : this.currentFile;
-    return `[${getTime(diff)}|% ${percent}` +
+    return `[${getTime(diff)}|% ${
-          `| ${fraction(completedFiles, scheduledFiles)} files ` +
+               percent}| ${
-          `| ${fraction(completedRunsForFile, runsPerFile)} runs ` +
+               fraction(completedFiles, scheduledFiles)} files | ${
-          `| ${fraction(completedConfig, scheduledConfig)} configs]` +
+               fraction(completedRunsForFile, runsPerFile)} runs | ${
-          `: ${caption} `;
+               fraction(completedConfig, scheduledConfig)} configs]: ${
+               caption} `;
   }
 
   updateProgress(finished) {

benchmark/_http-benchmarkers.js

@@ -4,6 +4,9 @@ const child_process = require('child_process');
 const path = require('path');
 const fs = require('fs');
 
+const requirementsURL =
+  'https://github.com/nodejs/node/blob/master/doc/guides/writing-and-running-benchmarks.md##http-benchmark-requirements';
+
 // The port used by servers and wrk
 exports.PORT = process.env.PORT || 12346;
 
@@ -133,20 +136,19 @@ exports.run = function(options, callback) {
     benchmarker: exports.default_http_benchmarker
   }, options);
   if (!options.benchmarker) {
-    callback(new Error('Could not locate required http benchmarker. See ' +
+    callback(new Error(`Could not locate required http benchmarker. See ${
-                       'https://github.com/nodejs/node/blob/master/doc/guides/writing-and-running-benchmarks.md##http-benchmark-requirements ' +
+                        requirementsURL} for further instructions.`));
-                       'for further instructions.'));
     return;
   }
   const benchmarker = benchmarkers[options.benchmarker];
   if (!benchmarker) {
-    callback(new Error(`Requested benchmarker '${options.benchmarker}' is ` +
+    callback(new Error(`Requested benchmarker '${
-                       'not supported'));
+                        options.benchmarker}' is  not supported`));
     return;
   }
   if (!benchmarker.present) {
-    callback(new Error(`Requested benchmarker '${options.benchmarker}' is ` +
+    callback(new Error(`Requested benchmarker '${
-                       'not installed'));
+                        options.benchmarker}' is  not installed`));
     return;
   }
 
@@ -172,8 +174,8 @@ exports.run = function(options, callback) {
 
     const result = benchmarker.processResults(stdout);
     if (result === undefined) {
-      callback(new Error(`${options.benchmarker} produced strange output: ` +
+      callback(new Error(
-                         stdout, code));
+        `${options.benchmarker} produced strange output: ${stdout}`, code));
       return;
     }
 

benchmark/assert/deepequal-typedarrays.js

@@ -2,8 +2,17 @@
 const common = require('../common.js');
 const assert = require('assert');
 const bench = common.createBenchmark(main, {
-  type: ('Int8Array Uint8Array Int16Array Uint16Array Int32Array Uint32Array ' +
+  type: [
-    'Float32Array Float64Array Uint8ClampedArray').split(' '),
+    'Int8Array',
+    'Uint8Array',
+    'Int16Array',
+    'Uint16Array',
+    'Int32Array',
+    'Uint32Array',
+    'Float32Array',
+    'Float64Array',
+    'Uint8ClampedArray',
+  ],
   n: [1],
   method: ['strict', 'nonstrict'],
   len: [1e6]

benchmark/buffers/buffer-base64-decode-wrapped.js

@@ -12,7 +12,7 @@ function main(conf) {
   const linesCount = 8 << 16;
   const bytesCount = charsPerLine * linesCount / 4 * 3;
 
-  const line = 'abcd'.repeat(charsPerLine / 4) + '\n';
+  const line = `${'abcd'.repeat(charsPerLine / 4)}\n`;
   const data = line.repeat(linesCount);
   // eslint-disable-next-line no-unescaped-regexp-dot
   data.match(/./);  // Flatten the string

benchmark/buffers/buffer-bytelength.js

@@ -28,7 +28,7 @@ function main(conf) {
   } else {
     for (var string of chars) {
       // Strings must be built differently, depending on encoding
-      var data = buildString(string, len);
+      var data = string.repeat(len);
       if (encoding === 'utf8') {
         strings.push(data);
       } else if (encoding === 'base64') {
@@ -54,9 +54,3 @@ function main(conf) {
   }
   bench.end(n);
 }
-
-function buildString(str, times) {
-  if (times === 1) return str;
-
-  return str + buildString(str, times - 1);
-}

benchmark/buffers/buffer-read.js

@@ -30,14 +30,14 @@ function main(conf) {
   var len = +conf.millions * 1e6;
   var clazz = conf.buf === 'fast' ? Buffer : require('buffer').SlowBuffer;
   var buff = new clazz(8);
-  var fn = 'read' + conf.type;
+  var fn = `read${conf.type}`;
 
   buff.writeDoubleLE(0, 0, noAssert);
-  var testFunction = new Function('buff', [
+  var testFunction = new Function('buff', `
-    'for (var i = 0; i !== ' + len + '; i++) {',
+    for (var i = 0; i !== ${len}; i++) {
-    '  buff.' + fn + '(0, ' + JSON.stringify(noAssert) + ');',
+      buff.${fn}(0, ${JSON.stringify(noAssert)});
-    '}'
+    }
-  ].join('\n'));
+  `);
   bench.start();
   testFunction(buff);
   bench.end(len / 1e6);

benchmark/buffers/buffer-swap.js

@@ -64,11 +64,11 @@ function createBuffer(len, aligned) {
 }
 
 function genMethod(method) {
-  const fnString =
+  const fnString = `
-      'return function ' + method + '(n, buf) {' +
+      return function ${method}(n, buf) {
-      '  for (var i = 0; i <= n; i++)' +
+        for (var i = 0; i <= n; i++)
-      '    buf.' + method + '();' +
+          buf.${method}();
-      '}';
+      }`;
   return (new Function(fnString))();
 }
 

benchmark/buffers/buffer-write.js

@@ -50,7 +50,7 @@ function main(conf) {
   var len = +conf.millions * 1e6;
   var clazz = conf.buf === 'fast' ? Buffer : require('buffer').SlowBuffer;
   var buff = new clazz(8);
-  var fn = 'write' + conf.type;
+  var fn = `write${conf.type}`;
 
   if (fn.match(/Int/))
     benchInt(buff, fn, len, noAssert);
@@ -60,22 +60,22 @@ function main(conf) {
 
 function benchInt(buff, fn, len, noAssert) {
   var m = mod[fn];
-  var testFunction = new Function('buff', [
+  var testFunction = new Function('buff', `
-    'for (var i = 0; i !== ' + len + '; i++) {',
+    for (var i = 0; i !== ${len}; i++) {
-    '  buff.' + fn + '(i & ' + m + ', 0, ' + JSON.stringify(noAssert) + ');',
+      buff.${fn}(i & ${m}, 0, ${JSON.stringify(noAssert)});
-    '}'
+    }
-  ].join('\n'));
+  `);
   bench.start();
   testFunction(buff);
   bench.end(len / 1e6);
 }
 
 function benchFloat(buff, fn, len, noAssert) {
-  var testFunction = new Function('buff', [
+  var testFunction = new Function('buff', `
-    'for (var i = 0; i !== ' + len + '; i++) {',
+    for (var i = 0; i !== ${len}; i++) {
-    '  buff.' + fn + '(i, 0, ' + JSON.stringify(noAssert) + ');',
+      buff.${fn}(i, 0, ${JSON.stringify(noAssert)});
-    '}'
+    }
-  ].join('\n'));
+  `);
   bench.start();
   testFunction(buff);
   bench.end(len / 1e6);

benchmark/buffers/dataview-set.js

@@ -44,7 +44,7 @@ function main(conf) {
   var ab = new ArrayBuffer(8);
   var dv = new DataView(ab, 0, 8);
   var le = /LE$/.test(conf.type);
-  var fn = 'set' + conf.type.replace(/[LB]E$/, '');
+  var fn = `set${conf.type.replace(/[LB]E$/, '')}`;
 
   if (/int/i.test(fn))
     benchInt(dv, fn, len, le);

benchmark/common.js

@@ -44,7 +44,7 @@ Benchmark.prototype._parseArgs = function(argv, configs) {
   for (const arg of argv) {
     const match = arg.match(/^(.+?)=([\s\S]*)$/);
     if (!match) {
-      console.error('bad argument: ' + arg);
+      console.error(`bad argument: ${arg}`);
       process.exit(1);
     }
     const config = match[1];
@@ -206,7 +206,7 @@ function formatResult(data) {
   // Construct configuration string, " A=a, B=b, ..."
   let conf = '';
   for (const key of Object.keys(data.conf)) {
-    conf += ' ' + key + '=' + JSON.stringify(data.conf[key]);
+    conf += ` ${key}=${JSON.stringify(data.conf[key])}`;
   }
 
   var rate = data.rate.toString().split('.');

benchmark/compare.js

@@ -79,14 +79,14 @@ if (showProgress) {
       // Construct configuration string, " A=a, B=b, ..."
       let conf = '';
       for (const key of Object.keys(data.conf)) {
-        conf += ' ' + key + '=' + JSON.stringify(data.conf[key]);
+        conf += ` ${key}=${JSON.stringify(data.conf[key])}`;
       }
       conf = conf.slice(1);
       // Escape quotes (") for correct csv formatting
       conf = conf.replace(/"/g, '""');
 
-      console.log(`"${job.binary}", "${job.filename}", "${conf}", ` +
+      console.log(`"${job.binary}", "${job.filename}", "${conf}", ${
-                  `${data.rate}, ${data.time}`);
+                   data.rate}, ${data.time}`);
       if (showProgress) {
         // One item in the subqueue has been completed.
         progress.completeConfig(data);

benchmark/crypto/cipher-stream.js

@@ -51,7 +51,7 @@ function main(conf) {
       message = Buffer.alloc(conf.len, 'b');
       break;
     default:
-      throw new Error('unknown message type: ' + conf.type);
+      throw new Error(`unknown message type: ${conf.type}`);
   }
 
   var fn = api === 'stream' ? streamWrite : legacyWrite;

benchmark/crypto/hash-stream-creation.js

@@ -36,7 +36,7 @@ function main(conf) {
       message = Buffer.alloc(conf.len, 'b');
       break;
     default:
-      throw new Error('unknown message type: ' + conf.type);
+      throw new Error(`unknown message type: ${conf.type}`);
   }
 
   var fn = api === 'stream' ? streamWrite : legacyWrite;

benchmark/crypto/hash-stream-throughput.js

@@ -35,7 +35,7 @@ function main(conf) {
       message = Buffer.alloc(conf.len, 'b');
       break;
     default:
-      throw new Error('unknown message type: ' + conf.type);
+      throw new Error(`unknown message type: ${conf.type}`);
   }
 
   var fn = api === 'stream' ? streamWrite : legacyWrite;

benchmark/crypto/rsa-encrypt-decrypt-throughput.js

@@ -10,10 +10,10 @@ var RSA_PublicPem = {};
 var RSA_PrivatePem = {};
 
 keylen_list.forEach(function(key) {
-  RSA_PublicPem[key] = fs.readFileSync(fixtures_keydir +
+  RSA_PublicPem[key] =
-                                       '/rsa_public_' + key + '.pem');
+    fs.readFileSync(`${fixtures_keydir}/rsa_public_${key}.pem`);
-  RSA_PrivatePem[key] = fs.readFileSync(fixtures_keydir +
+  RSA_PrivatePem[key] =
-                                        '/rsa_private_' + key + '.pem');
+    fs.readFileSync(`${fixtures_keydir}/rsa_private_${key}.pem`);
 });
 
 var bench = common.createBenchmark(main, {

benchmark/crypto/rsa-sign-verify-throughput.js

@@ -10,10 +10,10 @@ var RSA_PublicPem = {};
 var RSA_PrivatePem = {};
 
 keylen_list.forEach(function(key) {
-  RSA_PublicPem[key] = fs.readFileSync(fixtures_keydir +
+  RSA_PublicPem[key] =
-                                       '/rsa_public_' + key + '.pem');
+    fs.readFileSync(`${fixtures_keydir}/rsa_public_${key}.pem`);
-  RSA_PrivatePem[key] = fs.readFileSync(fixtures_keydir +
+  RSA_PrivatePem[key] =
-                                        '/rsa_private_' + key + '.pem');
+    fs.readFileSync(`${fixtures_keydir}/rsa_private_${key}.pem`);
 });
 
 var bench = common.createBenchmark(main, {

benchmark/es/map-bench.js

@@ -16,11 +16,11 @@ function runObject(n) {
   var i = 0;
   bench.start();
   for (; i < n; i++) {
-    m['i' + i] = i;
+    m[`i${i}`] = i;
-    m['s' + i] = String(i);
+    m[`s${i}`] = String(i);
-    assert.strictEqual(String(m['i' + i]), m['s' + i]);
+    assert.strictEqual(String(m[`i${i}`]), m[`s${i}`]);
-    m['i' + i] = undefined;
+    m[`i${i}`] = undefined;
-    m['s' + i] = undefined;
+    m[`s${i}`] = undefined;
   }
   bench.end(n / 1e6);
 }
@@ -30,11 +30,11 @@ function runNullProtoObject(n) {
   var i = 0;
   bench.start();
   for (; i < n; i++) {
-    m['i' + i] = i;
+    m[`i${i}`] = i;
-    m['s' + i] = String(i);
+    m[`s${i}`] = String(i);
-    assert.strictEqual(String(m['i' + i]), m['s' + i]);
+    assert.strictEqual(String(m[`i${i}`]), m[`s${i}`]);
-    m['i' + i] = undefined;
+    m[`i${i}`] = undefined;
-    m['s' + i] = undefined;
+    m[`s${i}`] = undefined;
   }
   bench.end(n / 1e6);
 }
@@ -44,11 +44,11 @@ function runNullProtoLiteralObject(n) {
   var i = 0;
   bench.start();
   for (; i < n; i++) {
-    m['i' + i] = i;
+    m[`i${i}`] = i;
-    m['s' + i] = String(i);
+    m[`s${i}`] = String(i);
-    assert.strictEqual(String(m['i' + i]), m['s' + i]);
+    assert.strictEqual(String(m[`i${i}`]), m[`s${i}`]);
-    m['i' + i] = undefined;
+    m[`i${i}`] = undefined;
-    m['s' + i] = undefined;
+    m[`s${i}`] = undefined;
   }
   bench.end(n / 1e6);
 }
@@ -61,11 +61,11 @@ function runStorageObject(n) {
   var i = 0;
   bench.start();
   for (; i < n; i++) {
-    m['i' + i] = i;
+    m[`i${i}`] = i;
-    m['s' + i] = String(i);
+    m[`s${i}`] = String(i);
-    assert.strictEqual(String(m['i' + i]), m['s' + i]);
+    assert.strictEqual(String(m[`i${i}`]), m[`s${i}`]);
-    m['i' + i] = undefined;
+    m[`i${i}`] = undefined;
-    m['s' + i] = undefined;
+    m[`s${i}`] = undefined;
   }
   bench.end(n / 1e6);
 }
@@ -73,10 +73,10 @@ function runStorageObject(n) {
 function fakeMap() {
   const m = {};
   return {
-    get(key) { return m['$' + key]; },
+    get(key) { return m[`$${key}`]; },
-    set(key, val) { m['$' + key] = val; },
+    set(key, val) { m[`$${key}`] = val; },
     get size() { return Object.keys(m).length; },
-    has(key) { return Object.prototype.hasOwnProperty.call(m, '$' + key); }
+    has(key) { return Object.prototype.hasOwnProperty.call(m, `$${key}`); }
   };
 }
 
@@ -85,11 +85,11 @@ function runFakeMap(n) {
   var i = 0;
   bench.start();
   for (; i < n; i++) {
-    m.set('i' + i, i);
+    m.set(`i${i}`, i);
-    m.set('s' + i, String(i));
+    m.set(`s${i}`, String(i));
-    assert.strictEqual(String(m.get('i' + i)), m.get('s' + i));
+    assert.strictEqual(String(m.get(`i${i}`)), m.get(`s${i}`));
-    m.set('i' + i, undefined);
+    m.set(`i${i}`, undefined);
-    m.set('s' + i, undefined);
+    m.set(`s${i}`, undefined);
   }
   bench.end(n / 1e6);
 }
@@ -99,11 +99,11 @@ function runMap(n) {
   var i = 0;
   bench.start();
   for (; i < n; i++) {
-    m.set('i' + i, i);
+    m.set(`i${i}`, i);
-    m.set('s' + i, String(i));
+    m.set(`s${i}`, String(i));
-    assert.strictEqual(String(m.get('i' + i)), m.get('s' + i));
+    assert.strictEqual(String(m.get(`i${i}`)), m.get(`s${i}`));
-    m.set('i' + i, undefined);
+    m.set(`i${i}`, undefined);
-    m.set('s' + i, undefined);
+    m.set(`s${i}`, undefined);
   }
   bench.end(n / 1e6);
 }

benchmark/fs/bench-realpath.js

@@ -22,7 +22,7 @@ function main(conf) {
   else if (type === 'resolved')
     resolvedPath(n);
   else
-    throw new Error('unknown "type": ' + type);
+    throw new Error(`unknown "type": ${type}`);
 }
 
 function relativePath(n) {

benchmark/fs/bench-realpathSync.js

@@ -24,7 +24,7 @@ function main(conf) {
   else if (type === 'resolved')
     resolvedPath(n);
   else
-    throw new Error('unknown "type": ' + type);
+    throw new Error(`unknown "type": ${type}`);
   bench.end(n);
 }
 

benchmark/http/_chunky_http_client.js

@@ -37,7 +37,7 @@ function main(conf) {
     for (var i = 0; i < extra_header_count; i++) {
       // Utilize first three powers of a small integer for an odd cycle and
       // because the fourth power of some integers overloads the server.
-      todo.push('X-Header-' + i + ': ' + headers[i % 3]);
+      todo.push(`X-Header-${i}: ${headers[i % 3]}`);
     }
     todo.push('');
     todo.push('');

benchmark/http/cluster.js

@@ -27,7 +27,7 @@ function main(conf) {
       return;
 
     setTimeout(function() {
-      var path = '/' + conf.type + '/' + conf.len;
+      var path = `/${conf.type}/${conf.len}`;
 
       bench.http({
         path: path,

benchmark/http/http_server_for_chunky_client.js

@@ -6,7 +6,7 @@ var fs = require('fs');
 var fork = require('child_process').fork;
 var common = require('../common.js');
 var test = require('../../test/common.js');
-var pep = path.dirname(process.argv[1]) + '/_chunky_http_client.js';
+var pep = `${path.dirname(process.argv[1])}/_chunky_http_client.js`;
 var PIPE = test.PIPE;
 
 try {
@@ -30,7 +30,7 @@ server = http.createServer(function(req, res) {
 });
 
 server.on('error', function(err) {
-  throw new Error('server error: ' + err);
+  throw new Error(`server error: ${err}`);
 });
 
 server.listen(PIPE);

benchmark/http/simple.js

@@ -16,8 +16,7 @@ function main(conf) {
   var server = require('../fixtures/simple-http-server.js')
   .listen(process.env.PORT || common.PORT)
   .on('listening', function() {
-    var path = '/' + conf.type + '/' + conf.len + '/' + conf.chunks + '/' +
+    var path = `/${conf.type}/${conf.len}/${conf.chunks}/${conf.res}`;
-               conf.res;
 
     bench.http({
       path: path,

benchmark/misc/console.js

@@ -21,7 +21,7 @@ var bench = common.createBenchmark(main, {
 const nullStream = createNullStream();
 
 function usingRestAndConcat(...args) {
-  nullStream.write('this is ' + args[0] + ' of ' + args[1] + '\n');
+  nullStream.write(`this is ${args[0]} of ${args[1]}\n`);
 }
 
 function usingRestAndSpreadTS(...args) {
@@ -37,15 +37,15 @@ function usingArgumentsAndApplyTS() {
 }
 
 function usingRestAndSpreadC(...args) {
-  nullStream.write(util.format(...args) + '\n');
+  nullStream.write(`${util.format(...args)}\n`);
 }
 
 function usingRestAndApplyC(...args) {
-  nullStream.write(util.format.apply(null, args) + '\n');
+  nullStream.write(`${util.format.apply(null, args)}\n`);
 }
 
 function usingArgumentsAndApplyC() {
-  nullStream.write(util.format.apply(null, arguments) + '\n');
+  nullStream.write(`${util.format.apply(null, arguments)}\n`);
 }
 
 function runUsingRestAndConcat(n) {

benchmark/misc/v8-bench.js

@@ -9,8 +9,8 @@ var dir = path.join(__dirname, '..', '..', 'deps', 'v8', 'benchmarks');
 
 function load(filename, inGlobal) {
   var source = fs.readFileSync(path.join(dir, filename), 'utf8');
-  if (!inGlobal) source = '(function () {' + source + '\n})()';
+  if (!inGlobal) source = `(function () {${source}\n})()`;
-  vm.runInThisContext(source, { filename: 'v8/bechmark/' + filename });
+  vm.runInThisContext(source, { filename: `v8/bechmark/${filename}` });
 }
 
 load('base.js', true);
@@ -41,13 +41,13 @@ global.BenchmarkSuite.RunSuites({
     });
   },
   NotifyError: function(name, error) {
-    console.error(name + ': ' + error);
+    console.error(`${name}: ${error}`);
   },
   NotifyScore: function(score) {
     common.sendResult({
       name: benchmark_name,
       conf: {
-        benchmark: 'Score (version ' + global.BenchmarkSuite.version + ')'
+        benchmark: `Score (version ${global.BenchmarkSuite.version})`
       },
       rate: score,
       time: 0

benchmark/module/module-loader.js

@@ -20,13 +20,13 @@ function main(conf) {
   try { fs.mkdirSync(benchmarkDirectory); } catch (e) {}
 
   for (var i = 0; i <= n; i++) {
-    fs.mkdirSync(benchmarkDirectory + i);
+    fs.mkdirSync(`${benchmarkDirectory}${i}`);
     fs.writeFileSync(
-      benchmarkDirectory + i + '/package.json',
+      `${benchmarkDirectory}${i}/package.json`,
       '{"main": "index.js"}'
     );
     fs.writeFileSync(
-      benchmarkDirectory + i + '/index.js',
+      `${benchmarkDirectory}${i}/index.js`,
       'module.exports = "";'
     );
   }
@@ -43,12 +43,12 @@ function measureFull(n, useCache) {
   var i;
   if (useCache) {
     for (i = 0; i <= n; i++) {
-      require(benchmarkDirectory + i + '/index.js');
+      require(`${benchmarkDirectory}${i}/index.js`);
     }
   }
   bench.start();
   for (i = 0; i <= n; i++) {
-    require(benchmarkDirectory + i + '/index.js');
+    require(`${benchmarkDirectory}${i}/index.js`);
   }
   bench.end(n / 1e3);
 }
@@ -57,12 +57,12 @@ function measureDir(n, useCache) {
   var i;
   if (useCache) {
     for (i = 0; i <= n; i++) {
-      require(benchmarkDirectory + i);
+      require(`${benchmarkDirectory}${i}`);
     }
   }
   bench.start();
   for (i = 0; i <= n; i++) {
-    require(benchmarkDirectory + i);
+    require(`${benchmarkDirectory}${i}`);
   }
   bench.end(n / 1e3);
 }

benchmark/net/net-c2s-cork.js

@@ -34,7 +34,7 @@ function main(conf) {
       chunk = 'x'.repeat(len);
       break;
     default:
-      throw new Error('invalid type: ' + type);
+      throw new Error(`invalid type: ${type}`);
   }
 
   server();

benchmark/net/net-c2s.js

@@ -34,7 +34,7 @@ function main(conf) {
       chunk = 'x'.repeat(len);
       break;
     default:
-      throw new Error('invalid type: ' + type);
+      throw new Error(`invalid type: ${type}`);
   }
 
   server();

benchmark/net/net-pipe.js

@@ -34,7 +34,7 @@ function main(conf) {
       chunk = 'x'.repeat(len);
       break;
     default:
-      throw new Error('invalid type: ' + type);
+      throw new Error(`invalid type: ${type}`);
   }
 
   server();

benchmark/net/net-s2c.js

@@ -34,7 +34,7 @@ function main(conf) {
       chunk = 'x'.repeat(len);
       break;
     default:
-      throw new Error('invalid type: ' + type);
+      throw new Error(`invalid type: ${type}`);
   }
 
   server();

benchmark/net/tcp-raw-c2s.js

@@ -89,7 +89,7 @@ function client() {
       chunk = 'x'.repeat(len);
       break;
     default:
-      throw new Error('invalid type: ' + type);
+      throw new Error(`invalid type: ${type}`);
   }
 
   var clientHandle = new TCP();

benchmark/net/tcp-raw-pipe.js

@@ -86,7 +86,7 @@ function client() {
       chunk = 'x'.repeat(len);
       break;
     default:
-      throw new Error('invalid type: ' + type);
+      throw new Error(`invalid type: ${type}`);
   }
 
   var clientHandle = new TCP();

benchmark/net/tcp-raw-s2c.js

@@ -60,7 +60,7 @@ function server() {
         chunk = 'x'.repeat(len);
         break;
       default:
-        throw new Error('invalid type: ' + type);
+        throw new Error(`invalid type: ${type}`);
     }
 
     clientHandle.readStart();

benchmark/path/basename-posix.js

@@ -21,7 +21,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var input = '' + conf.pathext;
+  var input = String(conf.pathext);
   var ext;
   var extIdx = input.indexOf('|');
   if (extIdx !== -1) {

benchmark/path/basename-win32.js

@@ -21,7 +21,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.pathext;
+  var input = String(conf.pathext);
   var ext;
   var extIdx = input.indexOf('|');
   if (extIdx !== -1) {

benchmark/path/dirname-posix.js

@@ -18,7 +18,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/dirname-win32.js

@@ -18,7 +18,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/extname-posix.js

@@ -21,7 +21,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/extname-win32.js

@@ -21,7 +21,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/format-posix.js

@@ -12,7 +12,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var props = ('' + conf.props).split('|');
+  var props = String(conf.props).split('|');
   var obj = {
     root: props[0] || '',
     dir: props[1] || '',

benchmark/path/format-win32.js

@@ -12,7 +12,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var props = ('' + conf.props).split('|');
+  var props = String(conf.props).split('|');
   var obj = {
     root: props[0] || '',
     dir: props[1] || '',

benchmark/path/isAbsolute-posix.js

@@ -16,7 +16,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/isAbsolute-win32.js

@@ -17,7 +17,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/join-posix.js

@@ -12,7 +12,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var args = ('' + conf.paths).split('|');
+  var args = String(conf.paths).split('|');
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/join-win32.js

@@ -12,7 +12,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var args = ('' + conf.paths).split('|');
+  var args = String(conf.paths).split('|');
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/makeLong-win32.js

@@ -15,7 +15,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/normalize-posix.js

@@ -17,7 +17,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/normalize-win32.js

@@ -17,7 +17,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/parse-posix.js

@@ -18,7 +18,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   for (var i = 0; i < n; i++) {
     p.parse(input);

benchmark/path/parse-win32.js

@@ -19,7 +19,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var input = '' + conf.path;
+  var input = String(conf.path);
 
   for (var i = 0; i < n; i++) {
     p.parse(input);

benchmark/path/relative-posix.js

@@ -18,7 +18,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var from = '' + conf.paths;
+  var from = String(conf.paths);
   var to = '';
   var delimIdx = from.indexOf('|');
   if (delimIdx > -1) {

benchmark/path/relative-win32.js

@@ -16,7 +16,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var from = '' + conf.paths;
+  var from = String(conf.paths);
   var to = '';
   var delimIdx = from.indexOf('|');
   if (delimIdx > -1) {

benchmark/path/resolve-posix.js

@@ -15,7 +15,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.posix;
-  var args = ('' + conf.paths).split('|');
+  var args = String(conf.paths).split('|');
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/path/resolve-win32.js

@@ -15,7 +15,7 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var n = +conf.n;
   var p = path.win32;
-  var args = ('' + conf.paths).split('|');
+  var args = String(conf.paths).split('|');
 
   bench.start();
   for (var i = 0; i < n; i++) {

benchmark/run.js

@@ -50,7 +50,7 @@ if (format === 'csv') {
     // Construct configuration string, " A=a, B=b, ..."
     let conf = '';
     for (const key of Object.keys(data.conf)) {
-      conf += ' ' + key + '=' + JSON.stringify(data.conf[key]);
+      conf += ` ${key}=${JSON.stringify(data.conf[key])}`;
     }
     // delete first space of the configuration
     conf = conf.slice(1);

benchmark/scatter.js

@@ -34,7 +34,7 @@ function csvEncodeValue(value) {
   if (typeof value === 'number') {
     return value.toString();
   } else {
-    return '"' + value.replace(/"/g, '""') + '"';
+    return `"${value.replace(/"/g, '""')}"`;
   }
 }
 

benchmark/timers/timers-cancel-unpooled.js

@@ -22,5 +22,5 @@ function main(conf) {
 }
 
 function cb() {
-  assert(false, 'Timer ' + this._idleTimeout + ' should not call callback');
+  assert(false, `Timer ${this._idleTimeout} should not call callback`);
 }

benchmark/timers/timers-insert-unpooled.js

@@ -23,5 +23,5 @@ function main(conf) {
 }
 
 function cb() {
-  assert(false, 'Timer ' + this._idleTimeout + ' should not call callback');
+  assert(false, `Timer ${this._idleTimeout} should not call callback`);
 }

benchmark/tls/throughput.js

@@ -38,9 +38,9 @@ function main(conf) {
   }
 
   options = {
-    key: fs.readFileSync(cert_dir + '/test_key.pem'),
+    key: fs.readFileSync(`${cert_dir}/test_key.pem`),
-    cert: fs.readFileSync(cert_dir + '/test_cert.pem'),
+    cert: fs.readFileSync(`${cert_dir}/test_cert.pem`),
-    ca: [ fs.readFileSync(cert_dir + '/test_ca.pem') ],
+    ca: [ fs.readFileSync(`${cert_dir}/test_ca.pem`) ],
     ciphers: 'AES256-GCM-SHA384'
   };
 

benchmark/tls/tls-connect.js

@@ -22,9 +22,9 @@ function main(conf) {
 
   var cert_dir = path.resolve(__dirname, '../../test/fixtures');
   var options = {
-    key: fs.readFileSync(cert_dir + '/test_key.pem'),
+    key: fs.readFileSync(`${cert_dir}/test_key.pem`),
-    cert: fs.readFileSync(cert_dir + '/test_cert.pem'),
+    cert: fs.readFileSync(`${cert_dir}/test_cert.pem`),
-    ca: [ fs.readFileSync(cert_dir + '/test_ca.pem') ],
+    ca: [ fs.readFileSync(`${cert_dir}/test_ca.pem`) ],
     ciphers: 'AES256-GCM-SHA384'
   };
 

benchmark/url/legacy-vs-whatwg-url-get-prop.js

@@ -48,7 +48,7 @@ function useWHATWG(n, input) {
   var obj = new URL(input);
   var noDead = {
     protocol: obj.protocol,
-    auth: obj.username + ':' + obj.password,
+    auth: `${obj.username}:${obj.password}`,
     host: obj.host,
     hostname: obj.hostname,
     port: obj.port,
@@ -59,7 +59,7 @@ function useWHATWG(n, input) {
   bench.start();
   for (var i = 0; i < n; i += 1) {
     noDead.protocol = obj.protocol;
-    noDead.auth = obj.username + ':' + obj.password;
+    noDead.auth = `${obj.username}:${obj.password}`;
     noDead.host = obj.host;
     noDead.hostname = obj.hostname;
     noDead.port = obj.port;