tests: update to typescript 3.9.7

build/build-bundle.js

@@ -35,7 +35,7 @@ const locales = fs.readdirSync(__dirname + '/../lighthouse-core/lib/i18n/locales
 
 // HACK: manually include the lighthouse-plugin-publisher-ads audits.
 /** @type {Array<string>} */
-// @ts-ignore
+// @ts-expect-error
 const pubAdsAudits = require('lighthouse-plugin-publisher-ads/plugin.js').audits.map(a => a.path);
 
 /** @param {string} file */
@@ -84,7 +84,7 @@ async function browserifyFile(entryPath, distPath) {
 
   // Don't include locales in DevTools.
   if (isDevtools(entryPath)) {
-    // @ts-ignore bundle.ignore does accept an array of strings.
+    // @ts-expect-error bundle.ignore does accept an array of strings.
     bundle.ignore(locales);
   }
 
@@ -171,7 +171,7 @@ async function cli(argv) {
   build(entryPath, distPath);
 }
 
-// @ts-ignore Test if called from the CLI or as a module.
+// @ts-expect-error Test if called from the CLI or as a module.
 if (require.main === module) {
   cli(process.argv);
 } else {

clients/devtools-entry.js

@@ -59,26 +59,25 @@ if (typeof module !== 'undefined' && module.exports) {
   // work for LH because of https://github.com/browserify/browserify/issues/968
   // Instead, since this file is only ever run in node for testing, expose a
   // bundle entry point as global.
-  // @ts-ignore
+  // @ts-expect-error
   global.runBundledLighthouse = lighthouse;
 }
 
 // Expose only in DevTools' worker
-// @ts-ignore
 if (typeof self !== 'undefined') {
   // TODO: refactor and delete `global.isDevtools`.
   global.isDevtools = true;
 
-  // @ts-ignore
+  // @ts-expect-error
   self.setUpWorkerConnection = setUpWorkerConnection;
-  // @ts-ignore
+  // @ts-expect-error
   self.runLighthouse = lighthouse;
-  // @ts-ignore
+  // @ts-expect-error
   self.createConfig = createConfig;
-  // @ts-ignore
+  // @ts-expect-error
   self.listenForStatus = listenForStatus;
-  // @ts-ignore
+  // @ts-expect-error
   self.registerLocaleData = registerLocaleData;
-  // @ts-ignore
+  // @ts-expect-error
   self.lookupLocale = lookupLocale;
 }

clients/devtools-report-assets.js

@@ -13,7 +13,7 @@
 
 /* global Runtime */
 
-// @ts-ignore: Runtime.cachedResources exists in Devtools. https://source.chromium.org/chromium/chromium/src/+/master:third_party/devtools-frontend/src/front_end/root/Runtime.js;l=1169
+// @ts-expect-error: Runtime.cachedResources exists in Devtools. https://source.chromium.org/chromium/chromium/src/+/master:third_party/devtools-frontend/src/front_end/root/Runtime.js;l=1169
 const cachedResources = Runtime.cachedResources;
 
 // Getters are necessary because the DevTools bundling processes

clients/lightrider/lightrider-entry.js

@@ -101,6 +101,6 @@ if (typeof module !== 'undefined' && module.exports) {
 
 // Expose on window for browser-residing consumers of file.
 if (typeof window !== 'undefined') {
-  // @ts-ignore
+  // @ts-expect-error - not worth typing a property on `window`.
   window.runLighthouseInLR = runLighthouseInLR;
 }

lighthouse-cli/bin.js

@@ -96,7 +96,7 @@ async function begin() {
     cliFlags.outputPath = 'stdout';
   }
 
-  // @ts-ignore - deprecation message for removed disableDeviceEmulation; can remove warning in v6.
+  // @ts-expect-error - deprecation message for removed disableDeviceEmulation; can remove warning in v6.
   if (cliFlags.disableDeviceEmulation) {
     log.warn('config', 'The "--disable-device-emulation" has been removed in v5.' +
         ' Please use "--emulated-form-factor=none" instead.');
@@ -107,8 +107,8 @@ async function begin() {
     // copied over to LH.Settings.extraHeaders, which is LH.Crdp.Network.Headers. Force
     // the conversion here, but long term either the CLI flag or the setting should have
     // a different name.
-    // @ts-ignore
-    let extraHeadersStr = /** @type {string} */ (cliFlags.extraHeaders);
+    /** @type {string} */
+    let extraHeadersStr = cliFlags.extraHeaders;
     // If not a JSON object, assume it's a path to a JSON file.
     if (extraHeadersStr.substr(0, 1) !== '{') {
       extraHeadersStr = fs.readFileSync(extraHeadersStr, 'utf-8');

lighthouse-cli/cli-flags.js

@@ -27,7 +27,7 @@ function flatten(arr) {
  * @return {LH.CliFlags}
  */
 function getFlags(manualArgv) {
-  // @ts-ignore yargs() is incorrectly typed as not accepting a single string.
+  // @ts-expect-error yargs() is incorrectly typed as not accepting a single string.
   const y = manualArgv ? yargs(manualArgv) : yargs;
   // Intentionally left as type `any` because @types/yargs doesn't chain correctly.
   const argv = y.help('help')

lighthouse-cli/sentry-prompt.js

@@ -40,7 +40,7 @@ function prompt() {
 
   const timeoutPromise = new Promise((resolve) => {
     timeout = setTimeout(() => {
-      // @ts-ignore Promise returned by prompt is decorated with `ui`
+      // @ts-expect-error Promise returned by prompt is decorated with `ui`
       prompt.ui.close();
       process.stdout.write('\n');
       log.warn('CLI', 'No response to error logging preference, errors will not be reported.');

lighthouse-cli/test/cli/bin-test.js

@@ -147,7 +147,7 @@ describe('CLI bin', function() {
 
   describe('extraHeaders', () => {
     it('should convert extra headers to object', async () => {
-      // @ts-ignore - see TODO: in bin.js
+      // @ts-expect-error - see TODO: in bin.js
       cliFlags = {...cliFlags, extraHeaders: '{"foo": "bar"}'};
       await bin.begin();
 
@@ -156,7 +156,7 @@ describe('CLI bin', function() {
 
     it('should read extra headers from file', async () => {
       const headersFile = require.resolve('../fixtures/extra-headers/valid.json');
-      // @ts-ignore - see TODO: in bin.js
+      // @ts-expect-error - see TODO: in bin.js
       cliFlags = {...cliFlags, extraHeaders: headersFile};
       await bin.begin();
 

lighthouse-cli/test/cli/cli-flags-test.js

@@ -14,14 +14,14 @@ describe('CLI bin', function() {
     getFlags('chrome://version');
     const yargs = require('yargs');
 
-    // @ts-ignore - getGroups is private
+    // @ts-expect-error - getGroups is private
     const optionGroups = yargs.getGroups();
     /** @type {string[]} */
     const allOptions = [];
     Object.keys(optionGroups).forEach(key => {
       allOptions.push(...optionGroups[key]);
     });
-    // @ts-ignore - getUsageInstance is private
+    // @ts-expect-error - getUsageInstance is private
     const optionsWithDescriptions = Object.keys(yargs.getUsageInstance().getDescriptions());
 
     allOptions.forEach(opt => {

lighthouse-cli/test/smokehouse/lighthouse-runners/bundle.js

@@ -15,11 +15,11 @@ const ChromeLauncher = require('chrome-launcher');
 const ChromeProtocol = require('../../../../lighthouse-core/gather/connections/cri.js');
 
 // Load bundle, which creates a `global.runBundledLighthouse`.
-// @ts-ignore - file won't exist until `yarn build-all`, but not used for types anyways.
+// @ts-ignore - file exists if `yarn build-all` is run, but not used for types anyways.
 require('../../../../dist/lighthouse-dt-bundle.js'); // eslint-disable-line
 
 /** @type {import('../../../../lighthouse-core/index.js')} */
-// @ts-ignore - not worth giving test global an actual type.
+// @ts-expect-error - not worth giving test global an actual type.
 const lighthouse = global.runBundledLighthouse;
 
 /**

lighthouse-cli/test/smokehouse/report-assert.js

@@ -277,9 +277,9 @@ function isPlainObject(obj) {
  * @param {Comparison} assertion
  */
 function reportAssertion(localConsole, assertion) {
-  // @ts-ignore - this doesn't exist now but could one day, so try not to break the future
+  // @ts-expect-error - this doesn't exist now but could one day, so try not to break the future
   const _toJSON = RegExp.prototype.toJSON;
-  // @ts-ignore
+  // @ts-expect-error
   // eslint-disable-next-line no-extend-native
   RegExp.prototype.toJSON = RegExp.prototype.toString;
 
@@ -312,7 +312,7 @@ function reportAssertion(localConsole, assertion) {
     }
   }
 
-  // @ts-ignore
+  // @ts-expect-error
   // eslint-disable-next-line no-extend-native
   RegExp.prototype.toJSON = _toJSON;
 }

lighthouse-core/audits/byte-efficiency/offscreen-images.js

@@ -215,7 +215,7 @@ class OffscreenImages extends ByteEfficiencyAudit {
       // Filter out images that were loaded after all CPU activity
       items = context.settings.throttlingMethod === 'simulate' ?
         OffscreenImages.filterLanternResults(unfilteredResults, lanternInteractive) :
-        // @ts-ignore - .timestamp will exist if throttlingMethod isn't lantern
+        // @ts-expect-error - .timestamp will exist if throttlingMethod isn't lantern
         OffscreenImages.filterObservedResults(unfilteredResults, interactive.timestamp);
     } catch (err) {
       // if the error is during a Lantern run, end of trace may also be inaccurate, so rethrow

lighthouse-core/audits/byte-efficiency/render-blocking-resources.js

@@ -135,9 +135,14 @@ class RenderBlockingResources extends Audit {
     const wastedCssBytes = await RenderBlockingResources.computeWastedCSSBytes(artifacts, context);
 
     const metricSettings = {throttlingMethod: 'simulate'};
+
+    /** @type {LH.Artifacts.MetricComputationData} */
+    // @ts-expect-error - TODO(bckenny): allow optional `throttling` settings
     const metricComputationData = {trace, devtoolsLog, simulator, settings: metricSettings};
-    // @ts-ignore - TODO(bckenny): allow optional `throttling` settings
-    const fcpSimulation = await FirstContentfulPaint.request(metricComputationData, context);
+
+    // Cast to just `LanternMetric` since we explicitly set `throttlingMethod: 'simulate'`.
+    const fcpSimulation = /** @type {LH.Artifacts.LanternMetric} */
+      (await FirstContentfulPaint.request(metricComputationData, context));
     const fcpTsInMs = traceOfTab.timestamps.firstContentfulPaint / 1000;
 
     const nodesByUrl = getNodesAndTimingByUrl(fcpSimulation.optimisticEstimate.nodeTimings);

lighthouse-core/audits/font-display.js

@@ -83,7 +83,7 @@ class FontDisplay extends Audit {
 
         // Finally convert the raw font URLs to the absolute URLs and add them to the set.
         const relativeURLs = rawFontURLs
-          // @ts-ignore - guaranteed to match from previous regex, pull URL group out
+          // @ts-expect-error - guaranteed to match from previous regex, pull URL group out
           .map(s => s.match(CSS_URL_REGEX)[1].trim())
           .map(s => {
             // remove any quotes surrounding the URL

lighthouse-core/audits/predictive-perf.js

@@ -46,7 +46,7 @@ class PredictivePerf extends Audit {
     const trace = artifacts.traces[Audit.DEFAULT_PASS];
     const devtoolsLog = artifacts.devtoolsLogs[Audit.DEFAULT_PASS];
     /** @type {LH.Config.Settings} */
-    // @ts-ignore - TODO(bckenny): allow optional `throttling` settings
+    // @ts-expect-error - TODO(bckenny): allow optional `throttling` settings
     const settings = {}; // Use default settings.
     const fcp = await LanternFcp.request({trace, devtoolsLog, settings}, context);
     const fmp = await LanternFmp.request({trace, devtoolsLog, settings}, context);

lighthouse-core/audits/screenshot-thumbnails.js

@@ -105,7 +105,7 @@ class ScreenshotThumbnails extends Audit {
       const targetTimestamp = speedline.beginning + timelineEnd * i / NUMBER_OF_THUMBNAILS;
 
       /** @type {SpeedlineFrame} */
-      // @ts-ignore - there will always be at least one frame by this point. TODO: use nonnullable assertion in TS2.9
+      // @ts-expect-error - there will always be at least one frame by this point. TODO: use nonnullable assertion in TS2.9
       let frameForTimestamp = null;
       if (i === NUMBER_OF_THUMBNAILS) {
         frameForTimestamp = analyzedFrames[analyzedFrames.length - 1];

lighthouse-core/audits/seo/hreflang.js

@@ -38,15 +38,15 @@ const str_ = i18n.createMessageInstanceIdFn(__filename, UIStrings);
  * @return {Array<string>}
  */
 function importValidLangs() {
-  // @ts-ignore - global switcheroo to load axe valid-langs
+  // @ts-expect-error - global switcheroo to load axe valid-langs
   const axeCache = global.axe;
-  // @ts-ignore
+  // @ts-expect-error
   global.axe = {utils: {}};
-  // @ts-ignore
+  // @ts-expect-error
   require('axe-core/lib/core/utils/valid-langs.js');
-  // @ts-ignore
+  // @ts-expect-error
   const validLangs = global.axe.utils.validLangs();
-  // @ts-ignore
+  // @ts-expect-error
   global.axe = axeCache;
 
   return validLangs;

lighthouse-core/audits/uses-rel-preload.js

@@ -172,7 +172,7 @@ class UsesRelPreloadAudit extends Audit {
     // Once we've modified the dependencies, simulate the new graph with flexible ordering.
     const simulationAfterChanges = simulator.simulate(modifiedGraph, {flexibleOrdering: true});
     const originalNodesByRecord = Array.from(simulationBeforeChanges.nodeTimings.keys())
-        // @ts-ignore we don't care if all nodes without a record collect on `undefined`
+        // @ts-expect-error we don't care if all nodes without a record collect on `undefined`
         .reduce((map, node) => map.set(node.record, node), new Map());
 
     const results = [];

lighthouse-core/computed/js-bundles.js

@@ -26,14 +26,14 @@ function computeGeneratedFileSizes(map, content) {
   // denotes nothing is mapped.
   const failureResult = {files: {}, unmappedBytes, totalBytes};
 
-  // @ts-ignore: This function is added in SDK.js. This will eventually be added to CDT.
+  // @ts-expect-error: This function is added in SDK.js. This will eventually be added to CDT.
   map.computeLastGeneratedColumns();
 
   for (const mapping of map.mappings()) {
     const source = mapping.sourceURL;
     const lineNum = mapping.lineNumber;
     const colNum = mapping.columnNumber;
-    // @ts-ignore: `lastColumnNumber` is not on types yet. This will eventually be added to CDT.
+    // @ts-expect-error: `lastColumnNumber` is not on types yet. This will eventually be added to CDT.
     const lastColNum = /** @type {number=} */ (mapping.lastColumnNumber);
 
     // Webpack sometimes emits null mappings.
@@ -99,7 +99,7 @@ class JSBundles {
 
       const compiledUrl = SourceMap.scriptUrl || 'compiled.js';
       const mapUrl = SourceMap.sourceMapUrl || 'compiled.js.map';
-      // @ts-ignore: CDT expects undefined properties to be explicit.
+      // Hack: CDT expects undefined properties to be explicit.
       const rawMapForCdt = /** @type {any} */ (rawMap);
       const map = new SDK.TextSourceMap(compiledUrl, mapUrl, rawMapForCdt);
 

lighthouse-core/computed/page-dependency-graph.js

@@ -253,12 +253,12 @@ class PageDependencyGraph {
 
         switch (evt.name) {
           case 'TimerInstall':
-            // @ts-ignore - 'TimerInstall' event means timerId exists.
+            // @ts-expect-error - 'TimerInstall' event means timerId exists.
             timers.set(evt.args.data.timerId, node);
             stackTraceUrls.forEach(url => addDependencyOnUrl(node, url));
             break;
           case 'TimerFire': {
-            // @ts-ignore - 'TimerFire' event means timerId exists.
+            // @ts-expect-error - 'TimerFire' event means timerId exists.
             const installer = timers.get(evt.args.data.timerId);
             if (!installer || installer.endTime > node.startTime) break;
             installer.addDependent(node);
@@ -273,37 +273,37 @@ class PageDependencyGraph {
 
           case 'EvaluateScript':
             addDependencyOnFrame(node, evt.args.data.frame);
-            // @ts-ignore - 'EvaluateScript' event means argsUrl is defined.
+            // @ts-expect-error - 'EvaluateScript' event means argsUrl is defined.
             addDependencyOnUrl(node, argsUrl);
             stackTraceUrls.forEach(url => addDependencyOnUrl(node, url));
             break;
 
           case 'XHRReadyStateChange':
             // Only create the dependency if the request was completed
-            // @ts-ignore - 'XHRReadyStateChange' event means readyState is defined.
+            // 'XHRReadyStateChange' event means readyState is defined.
             if (evt.args.data.readyState !== 4) break;
 
-            // @ts-ignore - 'XHRReadyStateChange' event means argsUrl is defined.
+            // @ts-expect-error - 'XHRReadyStateChange' event means argsUrl is defined.
             addDependencyOnUrl(node, argsUrl);
             stackTraceUrls.forEach(url => addDependencyOnUrl(node, url));
             break;
 
           case 'FunctionCall':
           case 'v8.compile':
             addDependencyOnFrame(node, evt.args.data.frame);
-            // @ts-ignore - events mean argsUrl is defined.
+            // @ts-expect-error - events mean argsUrl is defined.
             addDependencyOnUrl(node, argsUrl);
             break;
 
           case 'ParseAuthorStyleSheet':
             addDependencyOnFrame(node, evt.args.data.frame);
-            // @ts-ignore - 'ParseAuthorStyleSheet' event means styleSheetUrl is defined.
+            // @ts-expect-error - 'ParseAuthorStyleSheet' event means styleSheetUrl is defined.
             addDependencyOnUrl(node, evt.args.data.styleSheetUrl);
             break;
 
           case 'ResourceSendRequest':
             addDependencyOnFrame(node, evt.args.data.frame);
-            // @ts-ignore - 'ResourceSendRequest' event means requestId is defined.
+            // @ts-expect-error - 'ResourceSendRequest' event means requestId is defined.
             addDependentNetworkRequest(node, evt.args.data.requestId);
             stackTraceUrls.forEach(url => addDependencyOnUrl(node, url));
             break;
@@ -432,7 +432,7 @@ class PageDependencyGraph {
       const length = Math.ceil((node.endTime - node.startTime) / timePerCharacter);
       const bar = padRight('', offset) + padRight('', length, '=');
 
-      // @ts-ignore -- disambiguate displayName from across possible Node types.
+      // @ts-expect-error -- disambiguate displayName from across possible Node types.
       const displayName = node.record ? node.record.url : node.type;
       // eslint-disable-next-line
       console.log(padRight(bar, widthInCharacters), `| ${displayName.slice(0, 30)}`);

lighthouse-core/computed/unused-javascript-summary.js

@@ -121,14 +121,14 @@ class UnusedJavascriptSummary {
       return retVal;
     });
 
-    // @ts-ignore: We will upstream computeLastGeneratedColumns to CDT eventually.
+    // @ts-expect-error: We will upstream computeLastGeneratedColumns to CDT eventually.
     bundle.map.computeLastGeneratedColumns();
     for (const mapping of bundle.map.mappings()) {
       let offset = lineOffsets[mapping.lineNumber];
 
       offset += mapping.columnNumber;
       const lastColumnOfMapping =
-        // @ts-ignore: We will upstream lastColumnNumber to CDT eventually.
+        // @ts-expect-error: We will upstream lastColumnNumber to CDT eventually.
         (mapping.lastColumnNumber - 1) || lineLengths[mapping.lineNumber];
       for (let i = mapping.columnNumber; i <= lastColumnOfMapping; i++) {
         if (wasteData.every(data => data.unusedByIndex[offset] === 1)) {