core(runner): support multiple output modes

.gitignore

@@ -21,6 +21,7 @@ last-run-results.html
 *.report.html
 *.report.dom.html
 *.report.json
+*.report.csv
 *.report.pretty
 *.artifacts.log
 

lighthouse-cli/cli-flags.js

@@ -127,11 +127,12 @@ function getFlags(manualArgv) {
       .array('onlyAudits')
       .array('onlyCategories')
       .array('skipAudits')
+      .array('output')
       .string('extraHeaders')
 
       // default values
       .default('chrome-flags', '')
-      .default('output', 'html')
+      .default('output', ['html'])
       .default('port', 0)
       .default('hostname', 'localhost')
       .check(/** @param {!LH.Flags} argv */ (argv) => {

lighthouse-cli/printer.js

@@ -69,26 +69,17 @@ function writeFile(filePath, output, outputMode) {
 }
 
 /**
- * Writes the results.
- * @param {LH.RunnerResult} results
+ * Writes the output.
+ * @param {string} output
  * @param {string} mode
  * @param {string} path
- * @return {Promise<LH.RunnerResult>}
+ * @return {Promise<void>}
  */
-function write(results, mode, path) {
-  return new Promise((resolve, reject) => {
-    const outputPath = checkOutputPath(path);
-    const output = results.report;
-
-    if (outputPath === 'stdout') {
-      return writeToStdout(output).then(_ => resolve(results));
-    }
-    return writeFile(outputPath, output, mode)
-      .then(_ => {
-        resolve(results);
-      })
-      .catch(err => reject(err));
-  });
+async function write(output, mode, path) {
+  const outputPath = checkOutputPath(path);
+  return outputPath === 'stdout' ?
+    writeToStdout(output) :
+    writeFile(outputPath, output, mode);
 }
 
 /**

lighthouse-cli/run.js

@@ -99,13 +99,12 @@ function handleError(err) {
  * @param {!LH.Flags} flags
  * @return {Promise<void>}
  */
-function saveResults(runnerResult, flags) {
+async function saveResults(runnerResult, flags) {
   const cwd = process.cwd();
-  let promise = Promise.resolve();
 
   const shouldSaveResults = flags.auditMode || (flags.gatherMode === flags.auditMode);
-  if (!shouldSaveResults) return promise;
-  const {lhr, artifacts} = runnerResult;
+  if (!shouldSaveResults) return;
+  const {lhr, artifacts, report} = runnerResult;
 
   // Use the output path as the prefix for all generated files.
   // If no output path is set, generate a file prefix using the URL and date.
@@ -115,34 +114,26 @@ function saveResults(runnerResult, flags) {
   const resolvedPath = path.resolve(cwd, configuredPath);
 
   if (flags.saveAssets) {
-    promise = promise.then(_ => assetSaver.saveAssets(artifacts, lhr.audits, resolvedPath));
+    await assetSaver.saveAssets(artifacts, lhr.audits, resolvedPath);
   }
 
-  return promise.then(_ => {
-    if (Array.isArray(flags.output)) {
-      return flags.output.reduce((innerPromise, outputType) => {
-        const extension = outputType;
-        const outputPath = `${resolvedPath}.report.${extension}`;
-        return innerPromise.then(() => Printer.write(runnerResult, outputType, outputPath));
-      }, Promise.resolve());
-    } else {
-      const extension = flags.output;
-      const outputPath =
-          flags.outputPath || `${resolvedPath}.report.${extension}`;
-      return Printer.write(runnerResult, flags.output, outputPath).then(_ => {
-        if (flags.output === Printer.OutputMode[Printer.OutputMode.html]) {
-          if (flags.view) {
-            opn(outputPath, {wait: false});
-          } else {
-            log.log(
-                'CLI',
-                // eslint-disable-next-line max-len
-                'Protip: Run lighthouse with `--view` to immediately open the HTML report in your browser');
-          }
-        }
-      });
+  for (const outputType of flags.output) {
+    const extension = outputType;
+    const output = report[flags.output.indexOf(outputType)];
+    let outputPath = `${resolvedPath}.report.${extension}`;
+    // If there was only a single output and the user specified an outputPath, force usage of it.
+    if (flags.outputPath && flags.output.length === 1) outputPath = flags.outputPath;
+    await Printer.write(output, outputType, outputPath);
+
+    if (outputType === Printer.OutputMode[Printer.OutputMode.html]) {
+      if (flags.view) {
+        opn(outputPath, {wait: false});
+      } else {
+        // eslint-disable-next-line max-len
+        log.log('CLI', 'Protip: Run lighthouse with `--view` to immediately open the HTML report in your browser');
+      }
     }
-  });
+  }
 }
 
 /**

lighthouse-core/config/config.js

@@ -154,13 +154,15 @@ function cleanFlagsForSettings(flags = {}) {
   return settings;
 }
 
-function merge(base, extension) {
+// TODO(phulce): disentangle this merge function
+function merge(base, extension, overrwriteArrays = false) {
   // If the default value doesn't exist or is explicitly null, defer to the extending value
   if (typeof base === 'undefined' || base === null) {
     return extension;
   } else if (typeof extension === 'undefined') {
     return base;
   } else if (Array.isArray(extension)) {
+    if (overrwriteArrays) return extension;
     if (!Array.isArray(base)) throw new TypeError(`Expected array but got ${typeof base}`);
     const merged = base.slice();
     extension.forEach(item => {
@@ -171,7 +173,8 @@ function merge(base, extension) {
   } else if (typeof extension === 'object') {
     if (typeof base !== 'object') throw new TypeError(`Expected object but got ${typeof base}`);
     Object.keys(extension).forEach(key => {
-      base[key] = merge(base[key], extension[key]);
+      if (key === 'settings' && typeof base[key] === 'object') overrwriteArrays = true;
+      base[key] = merge(base[key], extension[key], overrwriteArrays);
     });
     return base;
   }
@@ -241,7 +244,7 @@ class Config {
     configJSON.passes = Config.expandGathererShorthandAndMergeOptions(configJSON.passes);
 
     // Override any applicable settings with CLI flags
-    configJSON.settings = merge(configJSON.settings || {}, cleanFlagsForSettings(flags));
+    configJSON.settings = merge(configJSON.settings || {}, cleanFlagsForSettings(flags), true);
 
     // Generate a limited config if specified
     if (Array.isArray(configJSON.settings.onlyCategories) ||
@@ -301,7 +304,7 @@ class Config {
    */
   static augmentWithDefaults(config) {
     const {defaultSettings, defaultPassConfig} = constants;
-    config.settings = merge(deepClone(defaultSettings), config.settings);
+    config.settings = merge(deepClone(defaultSettings), config.settings, true);
     if (config.passes) {
       config.passes = config.passes.map(pass => merge(deepClone(defaultPassConfig), pass));
     }

lighthouse-core/report/report-generator.js

@@ -88,24 +88,31 @@ class ReportGenerator {
   /**
    * Creates the results output in a format based on the `mode`.
    * @param {LH.Result} lhr
-   * @param {'json'|'html'|'csv'} outputMode
-   * @return {string}
+   * @param {LH.Config.Settings['output']} outputModes
+   * @return {string|string[]}
    */
-  static generateReport(lhr, outputMode) {
-    // HTML report.
-    if (outputMode === 'html') {
-      return ReportGenerator.generateReportHtml(lhr);
-    }
-    // CSV report.
-    if (outputMode === 'csv') {
-      return ReportGenerator.generateReportCSV(lhr);
-    }
-    // JSON report.
-    if (outputMode === 'json') {
-      return JSON.stringify(lhr, null, 2);
-    }
+  static generateReport(lhr, outputModes) {
+    const outputAsArray = Array.isArray(outputModes);
+    if (typeof outputModes === 'string') outputModes = [outputModes];
+
+    const output = outputModes.map(outputMode => {
+      // HTML report.
+      if (outputMode === 'html') {
+        return ReportGenerator.generateReportHtml(lhr);
+      }
+      // CSV report.
+      if (outputMode === 'csv') {
+        return ReportGenerator.generateReportCSV(lhr);
+      }
+      // JSON report.
+      if (outputMode === 'json') {
+        return JSON.stringify(lhr, null, 2);
+      }
+
+      throw new Error('Invalid output mode: ' + outputMode);
+    });
 
-    throw new Error('Invalid output mode: ' + outputMode);
+    return outputAsArray ? output : output[0];
   }
 }
 

lighthouse-core/test/config/config-test.js

@@ -436,6 +436,11 @@ describe('Config', () => {
     assert.ok(config.settings.nonsense === undefined, 'did not cleanup settings');
   });
 
+  it('allows overriding of array-typed settings', () => {
+    const config = new Config({extends: true}, {output: ['html']});
+    assert.deepStrictEqual(config.settings.output, ['html']);
+  });
+
   it('extends the full config', () => {
     class CustomAudit extends Audit {
       static get meta() {

lighthouse-core/test/report/report-generator-test.js

@@ -114,4 +114,11 @@ describe('ReportGenerator', () => {
       assert.ok(outputCheck.test(htmlOutput));
     });
   });
+
+  it('handles array of outputs', () => {
+    const [json, html] = ReportGenerator.generateReport(sampleResults, ['json', 'html']);
+    assert.doesNotThrow(_ => JSON.parse(json));
+    assert.ok(/<!doctype/gim.test(html));
+    assert.ok(/<html lang="en"/gim.test(html));
+  });
 });

lighthouse-core/test/runner-test.js

@@ -543,4 +543,21 @@ describe('Runner', () => {
       ]);
     });
   });
+
+  it('can handle array of outputs', async () => {
+    const url = 'https://example.com';
+    const config = new Config({
+      extends: 'lighthouse:default',
+      settings: {
+        onlyCategories: ['performance'],
+        output: ['json', 'html'],
+      },
+    });
+
+    const results = await Runner.run(null, {url, config, driverMock});
+    assert.ok(Array.isArray(results.report) && results.report.length === 2,
+      'did not return multiple reports');
+    assert.ok(JSON.parse(results.report[0]), 'did not return json output');
+    assert.ok(/<!doctype/.test(results.report[1]), 'did not return html output');
+  });
 });

typings/externs.d.ts

@@ -47,8 +47,10 @@ declare global {
       cpuSlowdownMultiplier?: number
     }
 
+    export type OutputMode = 'json' | 'html' | 'csv';
+
     interface SharedFlagsSettings {
-      output?: 'json' | 'html' | 'csv';
+      output?: OutputMode|OutputMode[];
       maxWaitForLoad?: number;
       blockedUrlPatterns?: string[] | null;
       additionalTraceCategories?: string | null;
@@ -88,7 +90,7 @@ declare global {
 
     export interface RunnerResult {
       lhr: Result;
-      report: string;
+      report: string|string[];
       artifacts: Artifacts;
     }