[tools] Modernize tools .mjs files

This is mostly an auto-conversion done by several tools.

- use let / const
- use arrow functions
- use template strings

There are some additional manual rewrite required to modernize the
code further.

Change-Id: I63a7a43b05b14b33ad9941350d3d5f26aab10ba0
Bug: v8:10667
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2519564Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71080}

tools/arguments.mjs

@@ -27,37 +27,37 @@ export class BaseArgumentsProcessor {
           'Default log file name is "' +
           this.result_.logFileName + '".\n');
     print('Options:');
-    for (var arg in this.argsDispatch_) {
-      var synonyms = [arg];
-      var dispatch = this.argsDispatch_[arg];
-      for (var synArg in this.argsDispatch_) {
+    for (const arg in this.argsDispatch_) {
+      const synonyms = [arg];
+      const dispatch = this.argsDispatch_[arg];
+      for (const synArg in this.argsDispatch_) {
         if (arg !== synArg && dispatch === this.argsDispatch_[synArg]) {
           synonyms.push(synArg);
           delete this.argsDispatch_[synArg];
         }
       }
-      print('  ' + synonyms.join(', ').padEnd(20) + " " + dispatch[2]);
+      print(`  ${synonyms.join(', ').padEnd(20)} ${dispatch[2]}`);
     }
     quit(2);
   }
 
   parse() {
     while (this.args_.length) {
-      var arg = this.args_.shift();
+      let arg = this.args_.shift();
       if (arg.charAt(0) != '-') {
         this.result_.logFileName = arg;
         continue;
       }
-      var userValue = null;
-      var eqPos = arg.indexOf('=');
+      let userValue = null;
+      const eqPos = arg.indexOf('=');
       if (eqPos != -1) {
         userValue = arg.substr(eqPos + 1);
         arg = arg.substr(0, eqPos);
       }
       if (arg in this.argsDispatch_) {
-        var dispatch = this.argsDispatch_[arg];
-        var property = dispatch[0];
-        var defaultValue = dispatch[1];
+        const dispatch = this.argsDispatch_[arg];
+        const property = dispatch[0];
+        const defaultValue = dispatch[1];
         if (typeof defaultValue == "function") {
           userValue = defaultValue(userValue);
         } else if (userValue == null) {

tools/codemap.mjs

@@ -90,7 +90,7 @@ export class CodeMap {
    * @param {number} to The destination address.
    */
   moveCode(from, to) {
-    var removedNode = this.dynamics_.remove(from);
+    const removedNode = this.dynamics_.remove(from);
     this.deleteAllCoveredNodes_(this.dynamics_, to, to + removedNode.value.size);
     this.dynamics_.insert(to, removedNode.value);
   }
@@ -102,7 +102,7 @@ export class CodeMap {
    * @param {number} start The starting address of the entry being deleted.
    */
   deleteCode(start) {
-    var removedNode = this.dynamics_.remove(start);
+    const removedNode = this.dynamics_.remove(start);
   }
 
   /**
@@ -130,7 +130,7 @@ export class CodeMap {
    * @private
    */
   markPages_(start, end) {
-    for (var addr = start; addr <= end;
+    for (let addr = start; addr <= end;
         addr += CodeMap.PAGE_SIZE) {
       this.pages_[(addr / CodeMap.PAGE_SIZE)|0] = 1;
     }
@@ -140,16 +140,16 @@ export class CodeMap {
    * @private
    */
   deleteAllCoveredNodes_(tree, start, end) {
-    var to_delete = [];
-    var addr = end - 1;
+    const to_delete = [];
+    let addr = end - 1;
     while (addr >= start) {
-      var node = tree.findGreatestLessThan(addr);
+      const node = tree.findGreatestLessThan(addr);
       if (!node) break;
-      var start2 = node.key, end2 = start2 + node.value.size;
+      const start2 = node.key, end2 = start2 + node.value.size;
       if (start2 < end && start < end2) to_delete.push(start2);
       addr = start2 - 1;
     }
-    for (var i = 0, l = to_delete.length; i < l; ++i) tree.remove(to_delete[i]);
+    for (let i = 0, l = to_delete.length; i < l; ++i) tree.remove(to_delete[i]);
   }
 
   /**
@@ -163,7 +163,7 @@ export class CodeMap {
    * @private
    */
   findInTree_(tree, addr) {
-    var node = tree.findGreatestLessThan(addr);
+    const node = tree.findGreatestLessThan(addr);
     return node && this.isAddressBelongsTo_(addr, node) ? node : null;
   }
 
@@ -175,29 +175,29 @@ export class CodeMap {
    * @param {number} addr Address.
    */
   findAddress(addr) {
-    var pageAddr = (addr / CodeMap.PAGE_SIZE)|0;
+    const pageAddr = (addr / CodeMap.PAGE_SIZE)|0;
     if (pageAddr in this.pages_) {
       // Static code entries can contain "holes" of unnamed code.
       // In this case, the whole library is assigned to this address.
-      var result = this.findInTree_(this.statics_, addr);
+      let result = this.findInTree_(this.statics_, addr);
       if (!result) {
         result = this.findInTree_(this.libraries_, addr);
         if (!result) return null;
       }
       return { entry : result.value, offset : addr - result.key };
     }
-    var min = this.dynamics_.findMin();
-    var max = this.dynamics_.findMax();
+    const min = this.dynamics_.findMin();
+    const max = this.dynamics_.findMax();
     if (max != null && addr < (max.key + max.value.size) && addr >= min.key) {
-      var dynaEntry = this.findInTree_(this.dynamics_, addr);
+      const dynaEntry = this.findInTree_(this.dynamics_, addr);
       if (dynaEntry == null) return null;
       // Dedupe entry name.
-      var entry = dynaEntry.value;
+      const entry = dynaEntry.value;
       if (!entry.nameUpdated_) {
         entry.name = this.dynamicsNameGen_.getName(entry.name);
         entry.nameUpdated_ = true;
       }
-      return { entry : entry, offset : addr - dynaEntry.key };
+      return { entry, offset : addr - dynaEntry.key };
     }
     return null;
   }
@@ -209,7 +209,7 @@ export class CodeMap {
    * @param {number} addr Address.
    */
   findEntry(addr) {
-    var result = this.findAddress(addr);
+    const result = this.findAddress(addr);
     return result ? result.entry : null;
   }
 
@@ -219,7 +219,7 @@ export class CodeMap {
    * @param {number} addr Address.
    */
   findDynamicEntryByStartAddress(addr) {
-    var node = this.dynamics_.find(addr);
+    const node = this.dynamics_.find(addr);
     return node ? node.value : null;
   }
 
@@ -292,7 +292,7 @@ class NameGenerator {
       this.knownNames_[name] = 0;
       return name;
     }
-    var count = ++this.knownNames_[name];
+    const count = ++this.knownNames_[name];
     return name + ' {' + count + '}';
   };
 }

tools/consarray.mjs

@@ -72,7 +72,7 @@ ConsArray.prototype.atEnd = function() {
  * Returns the current item, moves to the next one.
  */
 ConsArray.prototype.next = function() {
-  var result = this.currCell_.data[this.currCellPos_++];
+  const result = this.currCell_.data[this.currCellPos_++];
   if (this.currCellPos_ >= this.currCell_.data.length) {
     this.currCell_ = this.currCell_.next;
     this.currCellPos_ = 0;

tools/csvparser.mjs

@@ -84,9 +84,9 @@ export class CsvParser {
    * @param {string} line Input line.
    */
   parseLine(line) {
-    var pos = 0;
-    var endPos = line.length;
-    var fields = [];
+    let pos = 0;
+    const endPos = line.length;
+    const fields = [];
     if (endPos == 0) return fields;
     let nextPos = 0;
     while(nextPos !== -1) {

tools/dumpcpp-driver.mjs

@@ -11,7 +11,7 @@ import {
 // Dump C++ symbols of shared library if possible
 
 function processArguments(args) {
-  var processor = new ArgumentsProcessor(args);
+  const processor = new ArgumentsProcessor(args);
   if (processor.parse()) {
     return processor.result();
   } else {
@@ -25,26 +25,26 @@ function initSourceMapSupport() {
 
   // Overwrite the load function to load scripts synchronously.
   SourceMap.load = function(sourceMapURL) {
-    var content = readFile(sourceMapURL);
-    var sourceMapObject = (JSON.parse(content));
+    const content = readFile(sourceMapURL);
+    const sourceMapObject = (JSON.parse(content));
     return new SourceMap(sourceMapURL, sourceMapObject);
   };
 }
 
-var entriesProviders = {
+const entriesProviders = {
   'unix': UnixCppEntriesProvider,
   'windows': WindowsCppEntriesProvider,
   'mac': MacCppEntriesProvider
 };
 
-var params = processArguments(arguments);
-var sourceMap = null;
+const params = processArguments(arguments);
+let sourceMap = null;
 if (params.sourceMap) {
   initSourceMapSupport();
   sourceMap = SourceMap.load(params.sourceMap);
 }
 
-var cppProcessor = new CppProcessor(
+const cppProcessor = new CppProcessor(
   new (entriesProviders[params.platform])(params.nm, params.targetRootFS,
                                           params.apkEmbeddedLibrary),
   params.timedRange, params.pairwiseTimedRange);

tools/dumpcpp.mjs

@@ -33,7 +33,7 @@ export class CppProcessor extends LogReader {
 
   processLogFile(fileName) {
     this.lastLogFileName_ = fileName;
-    var line;
+    let line;
     while (line = readline()) {
       this.processLogLine(line);
     }
@@ -42,26 +42,26 @@ export class CppProcessor extends LogReader {
   processLogFileInTest(fileName) {
     // Hack file name to avoid dealing with platform specifics.
     this.lastLogFileName_ = 'v8.log';
-    var contents = readFile(fileName);
+    const contents = readFile(fileName);
     this.processLogChunk(contents);
   };
 
   processSharedLibrary(name, startAddr, endAddr, aslrSlide) {
-    var self = this;
-    var libFuncs = this.cppEntriesProvider_.parseVmSymbols(
+    const self = this;
+    const libFuncs = this.cppEntriesProvider_.parseVmSymbols(
         name, startAddr, endAddr, aslrSlide, function(fName, fStart, fEnd) {
-      var entry = new CodeEntry(fEnd - fStart, fName, 'CPP');
+      const entry = new CodeEntry(fEnd - fStart, fName, 'CPP');
       self.codeMap_.addStaticCode(fStart, entry);
     });
   };
 
   dumpCppSymbols() {
-    var staticEntries = this.codeMap_.getAllStaticEntriesWithAddresses();
-    var total = staticEntries.length;
-    for (var i = 0; i < total; ++i) {
-      var entry = staticEntries[i];
-      var printValues = ['cpp', '0x' + entry[0].toString(16), entry[1].size,
-                        '"' + entry[1].name + '"'];
+    const staticEntries = this.codeMap_.getAllStaticEntriesWithAddresses();
+    const total = staticEntries.length;
+    for (let i = 0; i < total; ++i) {
+      const entry = staticEntries[i];
+      const printValues = ['cpp', `0x${entry[0].toString(16)}`, entry[1].size,
+                        `"${entry[1].name}"`];
       print(printValues.join(','));
     }
   }

tools/ic-processor-driver.mjs

@@ -7,7 +7,7 @@ import { WebInspector } from "./sourcemap.mjs";
 import { BaseArgumentsProcessor } from "./arguments.mjs";
 
 function processArguments(args) {
-  var processor = new ArgumentsProcessor(args);
+  const processor = new ArgumentsProcessor(args);
   if (processor.parse()) {
     return processor.result();
   } else {
@@ -33,8 +33,8 @@ function initSourceMapSupport() {
 
   // Overwrite the load function to load scripts synchronously.
   SourceMap.load = function(sourceMapURL) {
-    var content = readFile(sourceMapURL);
-    var sourceMapObject = (JSON.parse(content));
+    const content = readFile(sourceMapURL);
+    const sourceMapObject = (JSON.parse(content));
     return new SourceMap(sourceMapURL, sourceMapObject);
   };
 }
@@ -82,7 +82,7 @@ for (const ic of processor.icTimeline.all) {
       ic.type + ' (' + ic.oldState + '->' + ic.newState + ic.modifier + ') at ' +
       ic.filePosition + ' ' + ic.key +
       ' (map 0x' + ic.map.toString(16) + ')' +
-      (ic.reason ? ' ' + ic.reason : '') + ' time: ' + ic.time);
+      (ic.reason ? ` ${ic.reason}` : '') + ' time: ' + ic.time);
   accumulator[ic.type]++;
 }
 

tools/logreader.mjs

@@ -146,11 +146,11 @@ LogReader.prototype.processLogLine = function(line) {
  * @return {Array.<number>} Processed stack.
  */
 LogReader.prototype.processStack = function(pc, func, stack) {
-  var fullStack = func ? [pc, func] : [pc];
-  var prevFrame = pc;
-  for (var i = 0, n = stack.length; i < n; ++i) {
-    var frame = stack[i];
-    var firstChar = frame.charAt(0);
+  const fullStack = func ? [pc, func] : [pc];
+  let prevFrame = pc;
+  for (let i = 0, n = stack.length; i < n; ++i) {
+    const frame = stack[i];
+    const firstChar = frame.charAt(0);
     if (firstChar == '+' || firstChar == '-') {
       // An offset from the previous frame.
       prevFrame += parseInt(frame, 16);
@@ -159,7 +159,7 @@ LogReader.prototype.processStack = function(pc, func, stack) {
     } else if (firstChar != 'o') {
       fullStack.push(parseInt(frame, 16));
     } else {
-      this.printError("dropping: " + frame);
+      this.printError(`dropping: ${frame}`);
     }
   }
   return fullStack;
@@ -172,9 +172,7 @@ LogReader.prototype.processStack = function(pc, func, stack) {
  * @param {!Object} dispatch Dispatch record.
  * @return {boolean} True if dispatch must be skipped.
  */
-LogReader.prototype.skipDispatch = function(dispatch) {
-  return false;
-};
+LogReader.prototype.skipDispatch = dispatch => false;
 
 // Parses dummy variable for readability;
 export const parseString = 'parse-string';
@@ -188,17 +186,17 @@ export const parseVarArgs = 'parse-var-args';
  */
 LogReader.prototype.dispatchLogRow_ = function(fields) {
   // Obtain the dispatch.
-  var command = fields[0];
-  var dispatch = this.dispatchTable_[command];
+  const command = fields[0];
+  const dispatch = this.dispatchTable_[command];
   if (dispatch === undefined) return;
   if (dispatch === null || this.skipDispatch(dispatch)) {
     return;
   }
 
   // Parse fields.
-  var parsedFields = [];
-  for (var i = 0; i < dispatch.parsers.length; ++i) {
-    var parser = dispatch.parsers[i];
+  const parsedFields = [];
+  for (let i = 0; i < dispatch.parsers.length; ++i) {
+    const parser = dispatch.parsers[i];
     if (parser === parseString) {
       parsedFields.push(fields[1 + i]);
     } else if (typeof parser == 'function') {
@@ -208,7 +206,7 @@ LogReader.prototype.dispatchLogRow_ = function(fields) {
       parsedFields.push(fields.slice(1 + i));
       break;
     } else {
-      throw new Error("Invalid log field parser: " + parser);
+      throw new Error(`Invalid log field parser: ${parser}`);
     }
   }
 
@@ -224,7 +222,7 @@ LogReader.prototype.dispatchLogRow_ = function(fields) {
  * @private
  */
 LogReader.prototype.processLog_ = function(lines) {
-  for (var i = 0, n = lines.length; i < n; ++i) {
+  for (let i = 0, n = lines.length; i < n; ++i) {
     this.processLogLine_(lines[i]);
   }
 }
@@ -238,10 +236,10 @@ LogReader.prototype.processLog_ = function(lines) {
 LogReader.prototype.processLogLine_ = function(line) {
   if (line.length > 0) {
     try {
-      var fields = this.csvParser_.parseLine(line);
+      const fields = this.csvParser_.parseLine(line);
       this.dispatchLogRow_(fields);
     } catch (e) {
-      this.printError('line ' + (this.lineNum_ + 1) + ': ' + (e.message || e) + '\n' + e.stack);
+      this.printError(`line ${this.lineNum_ + 1}: ${e.message || e}\n${e.stack}`);
     }
   }
   this.lineNum_++;

tools/parse-processor-driver.mjs

@@ -8,7 +8,7 @@ import {
   } from "./parse-processor.mjs";
 
 function processArguments(args) {
-  var processor = new ArgumentsProcessor(args);
+  const processor = new ArgumentsProcessor(args);
   if (processor.parse()) {
     return processor.result();
   } else {
@@ -22,17 +22,17 @@ function initSourceMapSupport() {
 
   // Overwrite the load function to load scripts synchronously.
   SourceMap.load = function(sourceMapURL) {
-    var content = readFile(sourceMapURL);
-    var sourceMapObject = (JSON.parse(content));
+    const content = readFile(sourceMapURL);
+    const sourceMapObject = (JSON.parse(content));
     return new SourceMap(sourceMapURL, sourceMapObject);
   };
 }
 
-var params = processArguments(arguments);
-var sourceMap = null;
+const params = processArguments(arguments);
+let sourceMap = null;
 if (params.sourceMap) {
   initSourceMapSupport();
   sourceMap = SourceMap.load(params.sourceMap);
 }
-var parseProcessor = new ParseProcessor();
+const parseProcessor = new ParseProcessor();
 parseProcessor.processLogFile(params.logFileName);

tools/parse-processor.mjs

 // Copyright 2017 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-"use strict";
-
 import { LogReader, parseString } from "./logreader.mjs";
 import { BaseArgumentsProcessor } from "./arguments.mjs";
 
@@ -339,7 +337,7 @@ class Script extends CompilationUnit {
 
   calculateMetrics(printSummary) {
     let log = (str) => this.summary += str + '\n';
-    log("SCRIPT: " + this.id);
+    log(`SCRIPT: ${this.id}`);
     let all = this.funktions;
     if (all.length === 0) return;
 
@@ -354,7 +352,7 @@ class Script extends CompilationUnit {
       let value = (funktions.length + "").padStart(6) +
         (nofPercent + "%").padStart(5) +
         BYTES(ownBytes, this.bytesTotal).padStart(10);
-      log(("  - " + name).padEnd(20) + value);
+      log((`  - ${name}`).padEnd(20) + value);
       this.metrics.set(name + "-bytes", ownBytes);
       this.metrics.set(name + "-count", funktions.length);
       this.metrics.set(name + "-count-percent", nofPercent);
@@ -362,7 +360,7 @@ class Script extends CompilationUnit {
         Math.round(ownBytes / this.bytesTotal * 100));
     };
 
-    log("  - file:         " + this.file);
+    log(`  - file:         ${this.file}`);
     log('  - details:      ' +
         'isEval=' + this.isEval + ' deserialized=' + this.isDeserialized +
         ' streamed=' + this.isStreamingCompiled);
@@ -409,7 +407,7 @@ class Script extends CompilationUnit {
     //   [start+delta*2, acc(metric0, start, start+delta*2), ...],
     //   ...
     // ]
-    if (end <= start) throw 'Invalid ranges [' + start + ',' + end + ']';
+    if (end <= start) throw `Invalid ranges [${start},${end}]`;
     const timespan = end - start;
     const kSteps = Math.ceil(timespan / delta);
     // To reduce the time spent iterating over the funktions of this script
@@ -607,8 +605,8 @@ class ExecutionCost {
   }
 
   toString() {
-    return ('  - ' + this.prefix + '-time:').padEnd(24) +
-      (" executed=" + formatNumber(this.executedCost) + 'ms').padEnd(20) +
+    return (`  - ${this.prefix}-time:`).padEnd(24) +
+      (` executed=${formatNumber(this.executedCost)}ms`).padEnd(20) +
       " non-executed=" + formatNumber(this.nonExecutedCost) + 'ms';
   }
 
@@ -623,11 +621,11 @@ class ExecutionCost {
 class Funktion extends CompilationUnit {
   constructor(name, start, end, script) {
     super();
-    if (start < 0) throw "invalid start position: " + start;
+    if (start < 0) throw `invalid start position: ${start}`;
     if (script.isEval) {
       if (end < start) throw 'invalid start end positions';
     } else {
-      if (end <= 0) throw 'invalid end position: ' + end;
+      if (end <= 0) throw `invalid end position: ${end}`;
       if (end <= start) throw 'invalid start end positions';
     }
 
@@ -722,7 +720,7 @@ class Funktion extends CompilationUnit {
   }
 
   toString(details = true) {
-    let result = 'function' + (this.name ? ' ' + this.name : '') +
+    let result = `function${this.name ? ` ${this.name}` : ''}` +
         `() range=${this.start}-${this.end}`;
     if (details) result += ` script=${this.script ? this.script.id : 'X'}`;
     return result;
@@ -841,7 +839,7 @@ export class ParseProcessor extends LogReader {
   processLogFile(fileName) {
     this.collectEntries = true
     this.lastLogFileName_ = fileName;
-    var line;
+    let line;
     while (line = readline()) {
       this.processLogLine(line);
     }
@@ -886,7 +884,7 @@ export class ParseProcessor extends LogReader {
       functionName) {
     let handlerFn = this.functionEventDispatchTable_[eventName];
     if (handlerFn === undefined) {
-      console.error('Couldn\'t find handler for function event:' + eventName);
+      console.error(`Couldn't find handler for function event:${eventName}`);
     }
     handlerFn(
         scriptId, startPosition, endPosition, duration, timestamp,
@@ -965,7 +963,7 @@ export class ParseProcessor extends LogReader {
         script.preparseTimestamp = toTimestamp(timestamp);
         return;
       default:
-        console.error('Unhandled script event: ' + eventName);
+        console.error(`Unhandled script event: ${eventName}`);
     }
   }
 

tools/profile_view.mjs

@@ -47,12 +47,12 @@ export function ViewBuilder(samplingRate) {
  */
 ViewBuilder.prototype.buildView = function(
     callTree, opt_bottomUpViewWeights) {
-  var head;
-  var samplingRate = this.samplingRate;
-  var createViewNode = this.createViewNode;
+  let head;
+  const samplingRate = this.samplingRate;
+  const createViewNode = this.createViewNode;
   callTree.traverse(function(node, viewParent) {
-    var totalWeight = node.totalWeight * samplingRate;
-    var selfWeight = node.selfWeight * samplingRate;
+    const totalWeight = node.totalWeight * samplingRate;
+    let selfWeight = node.selfWeight * samplingRate;
     if (opt_bottomUpViewWeights === true) {
       if (viewParent === head) {
         selfWeight = totalWeight;
@@ -60,7 +60,7 @@ ViewBuilder.prototype.buildView = function(
         selfWeight = 0;
       }
     }
-    var viewNode = createViewNode(node.label, totalWeight, selfWeight, head);
+    const viewNode = createViewNode(node.label, totalWeight, selfWeight, head);
     if (viewParent) {
       viewParent.addChild(viewNode);
     } else {
@@ -68,7 +68,7 @@ ViewBuilder.prototype.buildView = function(
     }
     return viewNode;
   });
-  var view = this.createView(head);
+  const view = this.createView(head);
   return view;
 };
 
@@ -79,9 +79,7 @@ ViewBuilder.prototype.buildView = function(
  * @param {ProfileView.Node} head View head node.
  * @return {ProfileView} Profile view.
  */
-ViewBuilder.prototype.createView = function(head) {
-  return new ProfileView(head);
-};
+ViewBuilder.prototype.createView = head => new ProfileView(head);
 
 
 /**
@@ -96,11 +94,11 @@ ViewBuilder.prototype.createView = function(head) {
  * @param {ProfileView.Node} head Profile view head.
  * @return {ProfileView.Node} Profile view node.
  */
-ViewBuilder.prototype.createViewNode = function(
-    funcName, totalTime, selfTime, head) {
-  return new ProfileView.Node(
-      funcName, totalTime, selfTime, head);
-};
+ViewBuilder.prototype.createViewNode = (
+    funcName, totalTime, selfTime, head) =>
+  new ProfileView.Node(
+      funcName, totalTime, selfTime, head)
+;
 
 
 /**
@@ -135,10 +133,10 @@ ProfileView.prototype.sort = function(sortFunc) {
  * @param {function(ProfileView.Node)} f Visitor function.
  */
 ProfileView.prototype.traverse = function(f) {
-  var nodesToTraverse = new ConsArray();
+  const nodesToTraverse = new ConsArray();
   nodesToTraverse.concat([this.head]);
   while (!nodesToTraverse.atEnd()) {
-    var node = nodesToTraverse.next();
+    const node = nodesToTraverse.next();
     f(node);
     nodesToTraverse.concat(node.children);
   }

tools/splaytree.mjs

@@ -75,7 +75,7 @@ SplayTree.prototype.insert = function(key, value) {
   if (this.root_.key == key) {
     return;
   }
-  var node = new SplayTree.Node(key, value);
+  const node = new SplayTree.Node(key, value);
   if (key > this.root_.key) {
     node.left = this.root_;
     node.right = this.root_.right;
@@ -99,17 +99,17 @@ SplayTree.prototype.insert = function(key, value) {
  */
 SplayTree.prototype.remove = function(key) {
   if (this.isEmpty()) {
-    throw Error('Key not found: ' + key);
+    throw Error(`Key not found: ${key}`);
   }
   this.splay_(key);
   if (this.root_.key != key) {
-    throw Error('Key not found: ' + key);
+    throw Error(`Key not found: ${key}`);
   }
-  var removed = this.root_;
+  const removed = this.root_;
   if (!this.root_.left) {
     this.root_ = this.root_.right;
   } else {
-    var right = this.root_.right;
+    const { right } = this.root_;
     this.root_ = this.root_.left;
     // Splay to make sure that the new root has an empty right child.
     this.splay_(key);
@@ -144,7 +144,7 @@ SplayTree.prototype.findMin = function() {
   if (this.isEmpty()) {
     return null;
   }
-  var current = this.root_;
+  let current = this.root_;
   while (current.left) {
     current = current.left;
   }
@@ -159,7 +159,7 @@ SplayTree.prototype.findMax = function(opt_startNode) {
   if (this.isEmpty()) {
     return null;
   }
-  var current = opt_startNode || this.root_;
+  let current = opt_startNode || this.root_;
   while (current.right) {
     current = current.right;
   }
@@ -195,7 +195,7 @@ SplayTree.prototype.findGreatestLessThan = function(key) {
  *     with keys.
  */
 SplayTree.prototype.exportKeysAndValues = function() {
-  var result = [];
+  const result = [];
   this.traverse_(function(node) { result.push([node.key, node.value]); });
   return result;
 };
@@ -205,7 +205,7 @@ SplayTree.prototype.exportKeysAndValues = function() {
  * @return {Array<*>} An array containing all the values of tree's nodes.
  */
 SplayTree.prototype.exportValues = function() {
-  var result = [];
+  const result = [];
   this.traverse_(function(node) { result.push(node.value); });
   return result;
 };
@@ -230,9 +230,9 @@ SplayTree.prototype.splay_ = function(key) {
   // the L tree of the algorithm.  The left child of the dummy node
   // will hold the R tree of the algorithm.  Using a dummy node, left
   // and right will always be nodes and we avoid special cases.
-  var dummy, left, right;
+  let dummy, left, right;
   dummy = left = right = new SplayTree.Node(null, null);
-  var current = this.root_;
+  let current = this.root_;
   while (true) {
     if (key < current.key) {
       if (!current.left) {
@@ -240,7 +240,7 @@ SplayTree.prototype.splay_ = function(key) {
       }
       if (key < current.left.key) {
         // Rotate right.
-        var tmp = current.left;
+        const tmp = current.left;
         current.left = tmp.right;
         tmp.right = current;
         current = tmp;
@@ -258,7 +258,7 @@ SplayTree.prototype.splay_ = function(key) {
       }
       if (key > current.right.key) {
         // Rotate left.
-        var tmp = current.right;
+        const tmp = current.right;
         current.right = tmp.left;
         tmp.left = current;
         current = tmp;
@@ -290,9 +290,9 @@ SplayTree.prototype.splay_ = function(key) {
  * @private
  */
 SplayTree.prototype.traverse_ = function(f) {
-  var nodesToVisit = [this.root_];
+  const nodesToVisit = [this.root_];
   while (nodesToVisit.length > 0) {
-    var node = nodesToVisit.shift();
+    const node = nodesToVisit.shift();
     if (node == null) {
       continue;
     }

tools/system-analyzer/ic-panel.mjs

@@ -55,16 +55,15 @@ DOM.defineCustomElement(
       }
 
       updateCount() {
-        this.count.innerHTML = 'length=' + this._selectedLogEntries.length;
+        this.count.innerHTML = `length=${this._selectedLogEntries.length}`;
       }
 
       updateTable(event) {
         let select = this.groupKey;
         let key = select.options[select.selectedIndex].text;
-        let tableBody = this.tableBody;
-        DOM.removeAllChildren(tableBody);
+        DOM.removeAllChildren(this.tableBody);
         let groups = Group.groupBy(this._selectedLogEntries, key, true);
-        this.render(groups, tableBody);
+        this.render(groups, this.tableBody);
       }
 
       escapeHtml(unsafe) {
@@ -89,8 +88,7 @@ DOM.defineCustomElement(
         // searches for mapLogEntries using the id, time
         const selectedMapLogEntriesSet = new Set();
         for (const icLogEntry of icLogEntries) {
-          const time = icLogEntry.time;
-          const selectedMap = MapLogEntry.get(id, time);
+          const selectedMap = MapLogEntry.get(id, icLogEntry.time);
           selectedMapLogEntriesSet.add(selectedMap);
         }
         return Array.from(selectedMapLogEntriesSet);
@@ -131,8 +129,7 @@ DOM.defineCustomElement(
         const omitted = groups.length - max;
         if (omitted > 0) {
           const tr = DOM.tr();
-          const tdNode =
-              tr.appendChild(DOM.td('Omitted ' + omitted + ' entries.'));
+          const tdNode = tr.appendChild(DOM.td(`Omitted ${omitted} entries.`));
           tdNode.colSpan = 4;
           fragment.appendChild(tr);
         }

tools/system-analyzer/log-file-reader.mjs

@@ -38,7 +38,7 @@ DOM.defineCustomElement('log-file-reader',
     event.preventDefault();
     this.dispatchEvent(
         new CustomEvent('fileuploadstart', {bubbles: true, composed: true}));
-    var host = event.dataTransfer ? event.dataTransfer : event.target;
+    const host = event.dataTransfer ? event.dataTransfer : event.target;
     this.readFile(host.files[0]);
   }
 
@@ -73,7 +73,7 @@ DOM.defineCustomElement('log-file-reader',
 
   handleFileLoad(e, file) {
     const chunk = e.target.result;
-    this.updateLabel('Finished loading \'' + file.name + '\'.');
+    this.updateLabel(`Finished loading '${file.name}'.`);
     this.dispatchEvent(new CustomEvent('fileuploadend', {
       bubbles: true,
       composed: true,

tools/system-analyzer/log/map.mjs

@@ -184,9 +184,9 @@ class Edge {
   }
 
   finishSetup() {
-    let from = this.from;
+    const from = this.from;
     if (from) from.addEdge(this);
-    let to = this.to;
+    const to = this.to;
     if (to === undefined) return;
     to.edge = this;
     if (from === undefined) return;

tools/system-analyzer/map-panel/map-details.mjs

@@ -29,9 +29,9 @@ DOM.defineCustomElement(
         let details = '';
         let clickableDetails = '';
         if (map) {
-          clickableDetails += 'ID: ' + map.id;
-          clickableDetails += '\nSource location: ' + map.filePosition;
-          details += '\n' + map.description;
+          clickableDetails += `ID: ${map.id}`;
+          clickableDetails += `\nSource location: ${map.filePosition}`;
+          details += `\n${map.description}`;
           this.setSelectedMap(map);
         }
         this._filePositionNode.innerText = clickableDetails;

tools/system-analyzer/map-panel/map-transitions.mjs

@@ -39,7 +39,7 @@ DOM.defineCustomElement('./map-panel/map-transitions',
   handleTransitionViewChange(e) {
     this.tooltip.style.left = e.pageX + 'px';
     this.tooltip.style.top = e.pageY + 'px';
-    let map = e.target.map;
+    const map = e.target.map;
     if (map) {
       this.tooltipContents.innerText = map.description;
     }

tools/system-analyzer/processor.mjs

@@ -125,7 +125,7 @@ export class Processor extends LogReader {
         this.processLogLine(line);
       }
     } catch (e) {
-      console.error('Error occurred during parsing, trying to continue: ' + e);
+      console.error(`Error occurred during parsing, trying to continue: ${e}`);
     }
     this.finalize();
   }
@@ -142,7 +142,7 @@ export class Processor extends LogReader {
       }
     } catch (e) {
       console.error(
-          'Error occurred during parsing line ' + i +
+          `Error occurred during parsing line ${i}` +
           ', trying to continue: ' + e);
     }
     this.finalize();
@@ -155,8 +155,8 @@ export class Processor extends LogReader {
     this._mapTimeline.forEach(map => {
       if (map.isRoot()) id = map.finalizeRootMap(id + 1);
       if (map.edge && map.edge.name) {
-        let edge = map.edge;
-        let list = this._mapTimeline.transitions.get(edge.name);
+        const edge = map.edge;
+        const list = this._mapTimeline.transitions.get(edge.name);
         if (list === undefined) {
           this._mapTimeline.transitions.set(edge.name, [edge]);
         } else {
@@ -178,13 +178,13 @@ export class Processor extends LogReader {
       case '*':
         return Profile.CodeState.OPTIMIZED;
     }
-    throw new Error('unknown code state: ' + s);
+    throw new Error(`unknown code state: ${s}`);
   }
 
   processCodeCreation(type, kind, timestamp, start, size, name, maybe_func) {
     if (maybe_func.length) {
-      let funcAddr = parseInt(maybe_func[0]);
-      let state = this.parseState(maybe_func[1]);
+      const funcAddr = parseInt(maybe_func[0]);
+      const state = this.parseState(maybe_func[1]);
       this._profile.addFuncCode(
           type, name, timestamp, start, size, funcAddr, state);
     } else {
@@ -324,7 +324,7 @@ export class Processor extends LogReader {
     if (id === '0x000000000000') return undefined;
     let map = MapLogEntry.get(id, time);
     if (map === undefined) {
-      console.error('No map details provided: id=' + id);
+      console.error(`No map details provided: id=${id}`);
       // Manually patch in a map to continue running.
       return this.createMapEntry(id, time);
     };

tools/system-analyzer/source-panel.mjs

@@ -188,12 +188,11 @@ class LineBuilder {
     this._selection = new Set(highlightPositions);
     this._clickHandler = panel.handleSourcePositionClick.bind(panel);
     // TODO: sort on script finalization.
-    script.sourcePositions
-        .sort((a, b) => {
-          if (a.line === b.line) return a.column - b.column;
-          return a.line - b.line;
-        }) this._sourcePositions =
-        new SourcePositionIterator(script.sourcePositions);
+    script.sourcePositions.sort((a, b) => {
+      if (a.line === b.line) return a.column - b.column;
+      return a.line - b.line;
+    });
+    this._sourcePositions = new SourcePositionIterator(script.sourcePositions);
   }
 
   get sourcePositionToMarkers() {

tools/system-analyzer/timeline/timeline-track.mjs

@@ -220,7 +220,6 @@ DOM.defineCustomElement('./timeline/timeline-track',
   }
 
   renderLegend() {
-    let timelineLegend = this.timelineLegend;
     let timelineLegendContent = this.timelineLegendContent;
     DOM.removeAllChildren(timelineLegendContent);
     this._timeline.uniqueTypes.forEach((entries, type) => {
@@ -249,7 +248,7 @@ DOM.defineCustomElement('./timeline/timeline-track',
     row.appendChild(DOM.td(this.data.all.length));
     row.appendChild(DOM.td('100%'));
     timelineLegendContent.appendChild(row);
-    timelineLegend.appendChild(timelineLegendContent);
+    this.timelineLegend.appendChild(timelineLegendContent);
   }
 
   handleEntryTypeDblClick(e) {
@@ -306,7 +305,7 @@ DOM.defineCustomElement('./timeline/timeline-track',
     }
 
     let imageData = this.backgroundCanvas.toDataURL('image/webp', 0.2);
-    node.style.backgroundImage = 'url(' + imageData + ')';
+    node.style.backgroundImage = `url(${imageData})`;
   }
 
   updateTimeline() {

tools/tickprocessor-driver.mjs

@@ -34,7 +34,7 @@ import {
 // Tick Processor's code flow.
 
 function processArguments(args) {
-  var processor = new ArgumentsProcessor(args);
+  const processor = new ArgumentsProcessor(args);
   if (processor.parse()) {
     return processor.result();
   } else {
@@ -48,25 +48,25 @@ function initSourceMapSupport() {
 
   // Overwrite the load function to load scripts synchronously.
   SourceMap.load = function(sourceMapURL) {
-    var content = readFile(sourceMapURL);
-    var sourceMapObject = (JSON.parse(content));
+    const content = readFile(sourceMapURL);
+    const sourceMapObject = (JSON.parse(content));
     return new SourceMap(sourceMapURL, sourceMapObject);
   };
 }
 
-var entriesProviders = {
+const entriesProviders = {
   'unix': UnixCppEntriesProvider,
   'windows': WindowsCppEntriesProvider,
   'mac': MacCppEntriesProvider
 };
 
-var params = processArguments(arguments);
-var sourceMap = null;
+const params = processArguments(arguments);
+let sourceMap = null;
 if (params.sourceMap) {
   initSourceMapSupport();
   sourceMap = SourceMap.load(params.sourceMap);
 }
-var tickProcessor = new TickProcessor(
+const tickProcessor = new TickProcessor(
   new (entriesProviders[params.platform])(params.nm, params.objdump, params.targetRootFS,
                                           params.apkEmbeddedLibrary),
   params.separateIc,