benchmark: refactor args parsing code

Author: IvanGoncharov

benchmark/benchmark.js

@@ -14,6 +14,15 @@ const maxTime = 5;
 // The minimum sample size required to perform statistical analysis.
 const minSamples = 5;
 
+// Get the revisions and make things happen!
+const { benchmarks, revisions } = getArguments(process.argv.slice(2));
+const benchmarkProjects = prepareBenchmarkProjects(revisions);
+
+runBenchmarks(benchmarks, benchmarkProjects).catch((error) => {
+  console.error(error);
+  process.exit(1);
+});
+
 function localDir(...paths) {
   return path.join(__dirname, '..', ...paths);
 }
@@ -230,9 +239,7 @@ function maxBy(array, fn) {
 }
 
 // Prepare all revisions and run benchmarks matching a pattern against them.
-async function runBenchmarks(benchmarks, revisions) {
-  const benchmarkProjects = prepareBenchmarkProjects(revisions);
-
+async function runBenchmarks(benchmarks, benchmarkProjects) {
   for (const benchmark of benchmarks) {
     const results = [];
     for (let i = 0; i < benchmarkProjects.length; ++i) {
@@ -266,31 +273,34 @@ async function runBenchmarks(benchmarks, revisions) {
 
 function getArguments(argv) {
   const revsIdx = argv.indexOf('--revs');
-  const revsArgs = revsIdx === -1 ? [] : argv.slice(revsIdx + 1);
-  const specificBenchmarks = revsIdx === -1 ? argv : argv.slice(0, revsIdx);
-  let assumeArgs;
-  let revisions;
-  switch (revsArgs.length) {
+  const revisions = revsIdx === -1 ? [] : argv.slice(revsIdx + 1);
+  const benchmarks = revsIdx === -1 ? argv : argv.slice(0, revsIdx);
+
+  switch (revisions.length) {
     case 0:
-      assumeArgs = [...specificBenchmarks, '--revs', 'local', 'HEAD'];
-      revisions = [LOCAL, 'HEAD'];
-      break;
+      revisions.unshift('HEAD');
     case 1:
-      assumeArgs = [...specificBenchmarks, '--revs', 'local', revsArgs[0]];
-      revisions = [LOCAL, revsArgs[0]];
-      break;
-    default:
-      revisions = revsArgs;
+      revisions.unshift('local');
+
+      const assumeArgv = ['benchmark', ...benchmarks, '--revs', ...revisions];
+      console.warn('Assuming you meant: ' + bold(assumeArgv.join(' ')));
       break;
   }
 
-  if (assumeArgs) {
-    console.warn(
-      'Assuming you meant: ' + bold('benchmark ' + assumeArgs.join(' ')),
-    );
+  if (benchmarks.length === 0) {
+    benchmarks.push(...findAllBenchmarks());
   }
 
-  return { specificBenchmarks, revisions };
+  return { benchmarks, revisions };
+}
+
+function findAllBenchmarks() {
+  return fs
+    .readdirSync(localDir('benchmark'), { withFileTypes: true })
+    .filter((dirent) => dirent.isFile())
+    .map((dirent) => dirent.name)
+    .filter((name) => name.endsWith('-benchmark.js'))
+    .map((name) => path.join('benchmark', name));
 }
 
 function bold(str) {
@@ -317,26 +327,6 @@ function grey(str) {
   return '\u001b[90m' + str + '\u001b[0m';
 }
 
-function findAllBenchmarks() {
-  return fs
-    .readdirSync(localDir('benchmark'), { withFileTypes: true })
-    .filter((dirent) => dirent.isFile())
-    .map((dirent) => dirent.name)
-    .filter((name) => name.endsWith('-benchmark.js'))
-    .map((name) => path.join('benchmark', name));
-}
-
-// Get the revisions and make things happen!
-if (require.main === module) {
-  const { specificBenchmarks, revisions } = getArguments(process.argv.slice(2));
-  const benchmarks =
-    specificBenchmarks.length > 0 ? specificBenchmarks : findAllBenchmarks();
-  runBenchmarks(benchmarks, revisions).catch((error) => {
-    console.error(error);
-    process.exit(1);
-  });
-}
-
 function sampleModule(modulePath) {
   const sampleCode = `
     const assert = require('assert');