feat(js): add benchmark support

js/src/runner.js

@@ -5,7 +5,7 @@ import minimist from 'minimist';
 import { Challenge } from './utils';
 
 const args = minimist(process.argv.slice(2));
-const exitCode = args['exit-code'];
+const { benchmark, 'exit-code': exitCode } = args;
 const requested = args._.map(Number);
 
 const isYear = (nr) => nr > 1000;
@@ -45,7 +45,7 @@ const isYear = (nr) => nr > 1000;
       // Find challenge for this requested year and day
       const challenge = challenges.find((c) => c.day === nr && c.year === year);
       if (challenge) {
-        await challenge.run();
+        await challenge.run({ benchmark });
       } else {
         throw new Error(`Could not find year ${year} day ${nr}`);
       }

js/src/utils/challenges/Challenge.js

@@ -7,7 +7,9 @@ import YAML from 'yaml';
 import colors from 'colors';
 import globby from 'globby';
 
-import { camelcase, time, titleize } from '..';
+import {
+  camelcase, sum, time, titleize,
+} from '..';
 
 const SRC_ROOT = 'src';
 const PUZZLE_ROOT = '../puzzles';
@@ -45,7 +47,7 @@ class Challenge {
     return import(path.resolve(this.path));
   }
 
-  async run() {
+  async run({ benchmark = false } = {}) {
     const parts = await this.parts();
     const { input: puzzleInput, examples } = this;
 
@@ -55,30 +57,61 @@ class Challenge {
         solution,
         puzzleInput,
         examples: examples[part],
+        benchmark,
       });
     }
   }
 
   async runPart({
-    part, solution, puzzleInput, examples = [],
+    part, solution, puzzleInput, examples = [], benchmark,
   } = {}) {
     const heading = `${this.year} · Day ${this.day} · ${titleize(part)}`;
     console.log(colors.cyan(heading));
 
+    const formatDuration = (duration) => {
+      if (!duration) return '';
+      if (duration < 1) return `${Math.ceil(duration * 1000)}μs`;
+      return `${Math.ceil(duration)}ms`;
+    };
+
     // Executes and times the solution (used for both puzzle input and examples)
+    const iterations = benchmark ? 1000 : 1;
     const execute = async (input, args = {}) => {
-      const [duration, answer] = await time(() => solution(input, args));
-      return { answer, duration };
+      const runs = [];
+      for (let i = 0; i < iterations; ++i) {
+        const [duration, answer] = await time(() => solution(input, args));
+        runs.push({ duration, answer });
+      }
+
+      // Only care about answer from the first run
+      const { duration, answer } = runs[0];
+
+      // Calculate benchmark stats
+      let bench;
+      if (iterations > 1) {
+        const durations = runs.map((run) => run.duration);
+        bench = {
+          avg: sum(durations) / iterations,
+          min: Math.min(...durations),
+          max: Math.max(...durations),
+          first: duration,
+        };
+      }
+
+      return { answer, duration, bench };
     };
 
     // Generic line rendering utility
-    const line = (label, text, correct, duration = null) => {
+    const line = (label, text, correct, duration = null, bench = null) => {
       const colored = correct ? colors.green(text) : colors.red(text);
       let suffix = '';
-      if (duration && duration < 1) {
-        suffix = ` ${colors.gray(`${Math.ceil(duration * 1000)}μs`)}`;
+      if (bench) {
+        const results = Object.entries(bench).map(([k, v]) => (
+          `${k}: ${formatDuration(v).padStart(5, ' ')}`
+        ));
+        suffix += `\n    ${colors.gray(`{ ${results.join(', ')} }`)}`;
       } else if (duration) {
-        suffix = ` ${colors.gray(`${Math.ceil(duration)}ms`)}`;
+        suffix += ` ${colors.gray(formatDuration(duration))}`;
       }
       console.log(` => ${label}: ${colored}${suffix}`);
     };
@@ -92,7 +125,7 @@ class Challenge {
         continue;
       }
 
-      const { answer, duration } = await execute(
+      const { answer, duration, bench } = await execute(
         input, example.args ? camelcaseKeysFor(example.args) : {},
       );
 
@@ -101,7 +134,7 @@ class Challenge {
         line(`Example ${colors.yellow(excerpt)}`, '[not yet solved]');
       } else {
         const text = passed ? answer : `${answer} (expected: ${expected})`;
-        line(`Example ${colors.yellow(excerpt)}`, text, passed, duration);
+        line(`Example ${colors.yellow(excerpt)}`, text, passed, duration, bench);
       }
       if (!passed) {
         console.log();
@@ -121,13 +154,13 @@ class Challenge {
       return;
     }
 
-    const { answer, duration } = await execute(puzzleInput);
+    const { answer, duration, bench } = await execute(puzzleInput);
     if (answer == null) {
       line('Answer', '[not yet solved]');
       console.log();
       return;
     }
-    line('Answer', answer, true, duration);
+    line('Answer', answer, true, duration, bench);
     console.log();
   }