src: add support to pretty and json output

README.md

@@ -14,3 +14,60 @@ packages operations.
 - [x] pinojs
 - [x] winston
 - [x] underscore
+
+## Running
+
+To a pretty terminal output, run `index.js`
+
+```console
+$ node index.js
+Running Node.js Package Benchmark...
+----------------------------------------------------------
+babel
+  transform (code=true ast=true):                         70.09 (3 samples)
+  transform (code=false):                                 78.57 (2 samples)
+dotenv
+  config:                                                 31.09K (5 samples)
+lodash
+  .chunk:                                                 24.47M (5 samples)
+  .groupBy:                                               3.343M (7 samples)
+  .includes:                                              10.35M (6 samples)
+  .orderBy:                                               921.3K (8 samples)
+moment
+  format (full):                                          504.7K (7 samples)
+  format:                                                 441K (4 samples)
+  fromNow (YYYYMMDD):                                     73K (9 samples)
+  subtract (10):                                          134K (5 samples)
+pinojs
+  info (10x):                                             109.1K (4 samples)
+prettier
+  format (semi=true):                                     773.5K (3 samples)
+  format (singleQuote=true semi=true tabs=true):          593.7K (3 samples)
+  format (singleQuote=false semi=false tabs=false):       473.4K (3 samples)
+underscore
+  .chunk:                                                 3.15M (3 samples)
+  .groupBy:                                               1.003M (3 samples)
+  .includes:                                              6.588M (4 samples)
+  .orderBy:                                               488.7K (5 samples)
+winston
+  info (10x):                                             24.48K (4 samples)
+```
+
+To store it as JSON, just pipe output to a file:
+
+```console
+$ node index.js > results.json
+$ cat result.json
+[
+  {
+    "name": "babel",
+    "method": "benchmarkjs",
+    "operations": [
+      {
+        "name": "transform (code=true ast=true)",
+        "opsSec": 67.80076532539411,
+        "samples": 3
+      },
+      {
+...
+```

console-output.js

@@ -0,0 +1,22 @@
+const opsSecFormatter = Intl.NumberFormat('en-US', { notation: 'compact', maximumSignificantDigits: 4})
+
+module.exports = {
+  log (str) {
+    console.log(str);
+  },
+  printResults (results) {
+    const halfScreen = process.stdout.columns / 2;
+    console.log('-'.repeat(halfScreen));
+    for (const result of results) {
+      console.log(`${result.name}`);
+      // TODO(rafaelgss): support non-operation method
+      for (const operation of result.operations) {
+        const opName = `  ${operation.name}:`;
+        const spaces = ' '.repeat(halfScreen - opName.length);
+        console.log(opName +
+        `${spaces}${opsSecFormatter.format(operation.opsSec)} (${operation.samples} samples)`);
+      }
+    }
+    console.log('-'.repeat(process.stdout.columns / 2));
+  }
+}

index.js

@@ -12,15 +12,32 @@ const piscina = new Piscina({
   maxQueue: 1,
 });
 
+let output;
+// Considering this script won't be called as a
+// child_process, stdout.isTTY should be reliable enough.
+if (process.env.TTY || process.stdout.isTTY) {
+  output = require('./console-output');
+} else {
+  output = {
+    log: () => {},
+    printResults: (results) => {
+      console.log(JSON.stringify(results, null, 2));
+    }
+  }
+}
+
 async function main() {
   const files = await fs.readdir(path.join(__dirname, './src'));
+  output.log('Running Node.js Package Benchmark...');
+  const results = [];
   for (const file of files) {
     if (file.match(/.*-benchmark\.js$/)) {
       const benchFile = path.join(__dirname, './src/', file);
       const result = await piscina.run(benchFile);
-      console.log('results', JSON.stringify(result, null, 2));
+      results.push(result);
     }
   }
+  output.printResults(results);
 }
 
 main();