From f70d9458e652ede123436cd2d0367012427399a0 Mon Sep 17 00:00:00 2001
From: Josh Goldberg <josh@fullscreenmario.com>
Date: Sat, 17 Feb 2018 13:39:55 -0500
Subject: [PATCH 1/2] Apply 'no-unnecessary-initializer' lint rule

Forbids `let`/`const` statements to be initialized to `undefined`, since that's the initial value by default anyway.
The auto-fixer also happened to remove two unnecessary `as number` casts in `src/harness/parallel/worker.ts`.

For historical data: to run with `--fix`, I modified the line in `Jakefile.js` that declared the `cmd` for running TSLint.
---
 src/compiler/checker.ts                 | 12 ++++++------
 src/compiler/core.ts                    |  4 ++--
 src/compiler/moduleNameResolver.ts      |  2 +-
 src/compiler/parser.ts                  |  8 ++++----
 src/compiler/transformers/utilities.ts  |  2 +-
 src/harness/fourslash.ts                |  6 +++---
 src/harness/harness.ts                  |  6 +++---
 src/harness/loggedIO.ts                 |  6 +++---
 src/harness/parallel/worker.ts          |  4 ++--
 src/harness/projectsRunner.ts           |  6 +++---
 src/server/client.ts                    |  2 +-
 src/server/session.ts                   |  4 ++--
 src/services/findAllReferences.ts       |  4 ++--
 src/services/patternMatcher.ts          |  6 +++---
 src/services/refactors/extractSymbol.ts | 22 +++++++++++-----------
 src/services/services.ts                |  2 +-
 src/services/utilities.ts               |  2 +-
 tslint.json                             |  1 -
 18 files changed, 49 insertions(+), 50 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2768c142f5aad..21e9d395bd2ed 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3152,7 +3152,7 @@ namespace ts {
                             }
                         }
 
-                        let entityName: EntityName = undefined;
+                        let entityName: EntityName;
                         const nameIdentifier = symbolToTypeReferenceName(type.symbol);
                         if (qualifiedName) {
                             Debug.assert(!qualifiedName.right);
@@ -5636,7 +5636,7 @@ namespace ts {
                 }
                 return [signature];
             }
-            let result: Signature[] = undefined;
+            let result: Signature[];
             for (let i = 0; i < signatureLists.length; i++) {
                 // Allow matching non-generic signatures to have excess parameters and different return types
                 const match = i === listIndex ? signature : findMatchingSignature(signatureLists[i], signature, /*partialMatch*/ true, /*ignoreThisTypes*/ true, /*ignoreReturnTypes*/ true);
@@ -5654,7 +5654,7 @@ namespace ts {
         // type is the union of the constituent return types.
         function getUnionSignatures(types: Type[], kind: SignatureKind): Signature[] {
             const signatureLists = map(types, t => getSignaturesOfType(t, kind));
-            let result: Signature[] = undefined;
+            let result: Signature[];
             for (let i = 0; i < signatureLists.length; i++) {
                 for (const signature of signatureLists[i]) {
                     // Only process signatures with parameter lists that aren't already in the result list
@@ -5790,7 +5790,7 @@ namespace ts {
             else {
                 // Combinations of function, class, enum and module
                 let members = emptySymbols;
-                let stringIndexInfo: IndexInfo = undefined;
+                let stringIndexInfo: IndexInfo;
                 if (symbol.exports) {
                     members = getExportsOfSymbol(symbol);
                 }
@@ -6332,7 +6332,7 @@ namespace ts {
             }
             const propTypes: Type[] = [];
             const declarations: Declaration[] = [];
-            let commonType: Type = undefined;
+            let commonType: Type;
             for (const prop of props) {
                 if (prop.declarations) {
                     addRange(declarations, prop.declarations);
@@ -6613,7 +6613,7 @@ namespace ts {
                 const parameters: Symbol[] = [];
                 let hasLiteralTypes = false;
                 let minArgumentCount = 0;
-                let thisParameter: Symbol = undefined;
+                let thisParameter: Symbol;
                 let hasThisParameter: boolean;
                 const iife = getImmediatelyInvokedFunctionExpression(declaration);
                 const isJSConstructSignature = isJSDocConstructSignature(declaration);
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 698824fa9b0fb..a4e024c7483a0 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1584,7 +1584,7 @@ namespace ts {
         return text.replace(/{(\d+)}/g, (_match, index?) => args[+index + baseIndex]);
     }
 
-    export let localizedDiagnosticMessages: MapLike<string> = undefined;
+    export let localizedDiagnosticMessages: MapLike<string>;
 
     export function getLocaleSpecificMessage(message: DiagnosticMessage) {
         return localizedDiagnosticMessages && localizedDiagnosticMessages[message.key] || message.message;
@@ -3043,7 +3043,7 @@ namespace ts {
 
     /** Return the object corresponding to the best pattern to match `candidate`. */
     export function findBestPatternMatch<T>(values: ReadonlyArray<T>, getPattern: (value: T) => Pattern, candidate: string): T | undefined {
-        let matchedValue: T | undefined = undefined;
+        let matchedValue: T | undefined;
         // use length of prefix as betterness criteria
         let longestMatchPrefixLength = -1;
 
diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 50181bb98e4f7..601556a5b7794 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -662,7 +662,7 @@ namespace ts {
         }
 
         // string is for exact match
-        let matchedPattern: Pattern | string | undefined = undefined;
+        let matchedPattern: Pattern | string | undefined;
         if (state.compilerOptions.paths) {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.paths_option_is_specified_looking_for_a_pattern_to_match_module_name_0, moduleName);
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 70ddb7b791df1..47d7b339a1058 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -4763,7 +4763,7 @@ namespace ts {
             const awaitToken = parseOptionalToken(SyntaxKind.AwaitKeyword);
             parseExpected(SyntaxKind.OpenParenToken);
 
-            let initializer: VariableDeclarationList | Expression = undefined;
+            let initializer: VariableDeclarationList | Expression;
             if (token() !== SyntaxKind.SemicolonToken) {
                 if (token() === SyntaxKind.VarKeyword || token() === SyntaxKind.LetKeyword || token() === SyntaxKind.ConstKeyword) {
                     initializer = parseVariableDeclarationList(/*inForStatementInitializer*/ true);
@@ -6090,7 +6090,7 @@ namespace ts {
             const typeReferenceDirectives: FileReference[] = [];
             const amdDependencies: { path: string; name: string }[] = [];
             let amdModuleName: string;
-            let checkJsDirective: CheckJsDirective = undefined;
+            let checkJsDirective: CheckJsDirective;
 
             // Keep scanning all the leading trivia in the file until we get to something that
             // isn't trivia.  Any single line comment will be analyzed to see if it is a
@@ -6313,7 +6313,7 @@ namespace ts {
                     // Initially we can parse out a tag.  We also have seen a starting asterisk.
                     // This is so that /** * @type */ doesn't parse.
                     let state = JSDocState.SawAsterisk;
-                    let margin: number | undefined = undefined;
+                    let margin: number | undefined;
                     // + 4 for leading '/** '
                     let indent = start - Math.max(content.lastIndexOf("\n", start), 0) + 4;
                     function pushComment(text: string) {
@@ -7337,7 +7337,7 @@ namespace ts {
             }
 
             function getLastChildWorker(node: Node): Node | undefined {
-                let last: Node = undefined;
+                let last: Node;
                 forEachChild(node, child => {
                     if (nodeIsPresent(child)) {
                         last = child;
diff --git a/src/compiler/transformers/utilities.ts b/src/compiler/transformers/utilities.ts
index f7d28d6b4fc3c..c64c1d169b8b8 100644
--- a/src/compiler/transformers/utilities.ts
+++ b/src/compiler/transformers/utilities.ts
@@ -48,7 +48,7 @@ namespace ts {
         const uniqueExports = createMap<boolean>();
         let exportedNames: Identifier[];
         let hasExportDefault = false;
-        let exportEquals: ExportAssignment = undefined;
+        let exportEquals: ExportAssignment;
         let hasExportStarsToExportValues = false;
         let hasImportStarOrImportDefault = false;
 
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index fa9bf124e5121..5c3ffdd46d91c 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -3317,7 +3317,7 @@ ${code}
         const ranges: Range[] = [];
 
         // Stuff related to the subfile we're parsing
-        let currentFileContent: string = undefined;
+        let currentFileContent: string;
         let currentFileName = fileName;
         let currentFileSymlinks: string[] | undefined;
         let currentFileOptions: { [s: string]: string } = {};
@@ -3452,7 +3452,7 @@ ${code}
     }
 
     function recordObjectMarker(fileName: string, location: LocationInformation, text: string, markerMap: ts.Map<Marker>, markers: Marker[]): Marker {
-        let markerValue: any = undefined;
+        let markerValue: any;
         try {
             // Attempt to parse the marker value as JSON
             markerValue = JSON.parse("{ " + text + " }");
@@ -3511,7 +3511,7 @@ ${code}
         let output = "";
 
         /// The current marker (or maybe multi-line comment?) we're parsing, possibly
-        let openMarker: LocationInformation = undefined;
+        let openMarker: LocationInformation;
 
         /// A stack of the open range markers that are still unclosed
         const openRanges: RangeLocationInformation[] = [];
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index e35ecba2a04ca..eb41565f0d231 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -145,7 +145,7 @@ namespace Utils {
             path = "tests/" + path;
         }
 
-        let content: string = undefined;
+        let content: string;
         try {
             content = Harness.IO.readFile(Harness.userSpecifiedRoot + path);
         }
@@ -1891,9 +1891,9 @@ namespace Harness {
             const lines = Utils.splitContentByNewlines(code);
 
             // Stuff related to the subfile we're parsing
-            let currentFileContent: string = undefined;
+            let currentFileContent: string;
             let currentFileOptions: any = {};
-            let currentFileName: any = undefined;
+            let currentFileName: any;
             let refs: string[] = [];
 
             for (const line of lines) {
diff --git a/src/harness/loggedIO.ts b/src/harness/loggedIO.ts
index 949c6e5d947c7..e87402ea14008 100644
--- a/src/harness/loggedIO.ts
+++ b/src/harness/loggedIO.ts
@@ -87,9 +87,9 @@ interface PlaybackControl {
 }
 
 namespace Playback {
-    let recordLog: IoLog = undefined;
-    let replayLog: IoLog = undefined;
-    let replayFilesRead: ts.Map<IoLogFile> | undefined = undefined;
+    let recordLog: IoLog;
+    let replayLog: IoLog;
+    let replayFilesRead: ts.Map<IoLogFile> | undefined;
     let recordLogFileNameBase = "";
 
     interface Memoized<T> {
diff --git a/src/harness/parallel/worker.ts b/src/harness/parallel/worker.ts
index 1902ff70b1933..00c86d4894c8e 100644
--- a/src/harness/parallel/worker.ts
+++ b/src/harness/parallel/worker.ts
@@ -55,7 +55,7 @@ namespace Harness.Parallel.Worker {
             retries() { return this; },
             slow() { return this; },
             timeout(n) {
-                timeout = n as number;
+                timeout = n;
                 return this;
             },
         };
@@ -127,7 +127,7 @@ namespace Harness.Parallel.Worker {
         const fakeContext: Mocha.ITestCallbackContext = {
             skip() { return this; },
             timeout(n) {
-                timeout = n as number;
+                timeout = n;
                 const timeoutMsg: ParallelTimeoutChangeMessage = { type: "timeout", payload: { duration: timeout } };
                 process.send(timeoutMsg);
                 return this;
diff --git a/src/harness/projectsRunner.ts b/src/harness/projectsRunner.ts
index f8d4d171f01df..7dbfe0c5a75f3 100644
--- a/src/harness/projectsRunner.ts
+++ b/src/harness/projectsRunner.ts
@@ -163,7 +163,7 @@ class ProjectRunner extends RunnerBase {
             }
 
             function getSourceFile(fileName: string, languageVersion: ts.ScriptTarget): ts.SourceFile {
-                let sourceFile: ts.SourceFile = undefined;
+                let sourceFile: ts.SourceFile;
                 if (fileName === Harness.Compiler.defaultLibFileName) {
                     sourceFile = Harness.Compiler.getDefaultLibrarySourceFile(Harness.Compiler.getDefaultLibFileName(compilerOptions));
                 }
@@ -294,7 +294,7 @@ class ProjectRunner extends RunnerBase {
             }
 
             function getSourceFileText(fileName: string): string {
-                let text: string = undefined;
+                let text: string;
                 try {
                     text = Harness.IO.readFile(getFileNameInTheProjectTest(fileName));
                 }
@@ -370,7 +370,7 @@ class ProjectRunner extends RunnerBase {
                     allInputFiles.unshift({ emittedFileName: sourceFile.fileName, code: sourceFile.text });
                 }
                 else if (!(compilerOptions.outFile || compilerOptions.out)) {
-                    let emitOutputFilePathWithoutExtension: string = undefined;
+                    let emitOutputFilePathWithoutExtension: string;
                     if (compilerOptions.outDir) {
                         let sourceFilePath = ts.getNormalizedAbsolutePath(sourceFile.fileName, compilerResult.program.getCurrentDirectory());
                         sourceFilePath = sourceFilePath.replace(compilerResult.program.getCommonSourceDirectory(), "");
diff --git a/src/server/client.ts b/src/server/client.ts
index cee65c0e5a485..6ffe05790a017 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -617,7 +617,7 @@ namespace ts.server {
             const edits: FileTextChanges[] = this.convertCodeEditsToTextChanges(response.body.edits);
 
             const renameFilename: string | undefined = response.body.renameFilename;
-            let renameLocation: number | undefined = undefined;
+            let renameLocation: number | undefined;
             if (renameFilename !== undefined) {
                 renameLocation = this.lineOffsetToPosition(renameFilename, response.body.renameLocation);
             }
diff --git a/src/server/session.ts b/src/server/session.ts
index bff19d7bc232f..3b727ccadf69a 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1541,7 +1541,7 @@ namespace ts.server {
         }
 
         private extractPositionAndRange(args: protocol.FileLocationOrRangeRequestArgs, scriptInfo: ScriptInfo): { position: number, textRange: TextRange } {
-            let position: number = undefined;
+            let position: number;
             let textRange: TextRange;
             if (this.isLocation(args)) {
                 position = getPosition(args);
@@ -1657,7 +1657,7 @@ namespace ts.server {
         }
 
         private getStartAndEndPosition(args: protocol.FileRangeRequestArgs, scriptInfo: ScriptInfo) {
-            let startPosition: number = undefined, endPosition: number = undefined;
+            let startPosition: number, endPosition: number;
             if (args.startPosition !== undefined) {
                 startPosition = args.startPosition;
             }
diff --git a/src/services/findAllReferences.ts b/src/services/findAllReferences.ts
index 8100a021fb8ba..af0fca5b0ea52 100644
--- a/src/services/findAllReferences.ts
+++ b/src/services/findAllReferences.ts
@@ -511,7 +511,7 @@ namespace ts.FindAllReferences.Core {
             // here appears to be intentional).
             const {
                 text = stripQuotes(unescapeLeadingUnderscores((getLocalSymbolForExportDefault(symbol) || symbol).escapedName)),
-                allSearchSymbols = undefined,
+                allSearchSymbols,
             } = searchOptions;
             const escapedText = escapeLeadingUnderscores(text);
             const parents = this.options.implementations && getParentSymbolsOfPropertyAccess(location, symbol, this.checker);
@@ -1148,7 +1148,7 @@ namespace ts.FindAllReferences.Core {
     }
 
     function getContainingTypeReference(node: Node): Node {
-        let topLevelTypeReference: Node = undefined;
+        let topLevelTypeReference: Node;
 
         while (node) {
             if (isTypeNode(node)) {
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index db957816146bb..14a9a73a9e1c5 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -336,7 +336,7 @@ namespace ts {
             // Only if all words have some sort of match is the pattern considered matched.
 
             const subWordTextChunks = segment.subWordTextChunks;
-            let matches: PatternMatch[] = undefined;
+            let matches: PatternMatch[];
 
             for (const subWordTextChunk of subWordTextChunks) {
                 // Try to match the candidate with this word
@@ -393,8 +393,8 @@ namespace ts {
 
             let currentCandidate = 0;
             let currentChunkSpan = 0;
-            let firstMatch: number = undefined;
-            let contiguous: boolean = undefined;
+            let firstMatch: number;
+            let contiguous: boolean;
 
             while (true) {
                 // Let's consider our termination cases
diff --git a/src/services/refactors/extractSymbol.ts b/src/services/refactors/extractSymbol.ts
index 65c9fd6268c3e..25a243c93df92 100644
--- a/src/services/refactors/extractSymbol.ts
+++ b/src/services/refactors/extractSymbol.ts
@@ -274,7 +274,7 @@ namespace ts.refactor.extractSymbol {
             }
             else if (isVariableStatement(node)) {
                 let numInitializers = 0;
-                let lastInitializer: Expression | undefined = undefined;
+                let lastInitializer: Expression | undefined;
                 for (const declaration of node.declarationList.declarations) {
                     if (declaration.initializer) {
                         numInitializers++;
@@ -730,12 +730,12 @@ namespace ts.refactor.extractSymbol {
 
         const functionName = createIdentifier(functionNameText);
 
-        let returnType: TypeNode = undefined;
+        let returnType: TypeNode;
         const parameters: ParameterDeclaration[] = [];
         const callArguments: Identifier[] = [];
         let writes: UsageEntry[];
         usagesInScope.forEach((usage, name) => {
-            let typeNode: TypeNode = undefined;
+            let typeNode: TypeNode;
             if (!isJS) {
                 let type = checker.getTypeOfSymbolAtLocation(usage.symbol, usage.node);
                 // Widen the type so we don't emit nonsense annotations like "function fn(x: 3) {"
@@ -1114,7 +1114,7 @@ namespace ts.refactor.extractSymbol {
     }
 
     function getContainingVariableDeclarationIfInList(node: Node, scope: Scope) {
-        let prevNode = undefined;
+        let prevNode;
         while (node !== undefined && node !== scope) {
             if (isVariableDeclaration(node) &&
                 node.initializer === prevNode &&
@@ -1161,7 +1161,7 @@ namespace ts.refactor.extractSymbol {
     }
 
     function getFirstDeclaration(type: Type): Declaration | undefined {
-        let firstDeclaration = undefined;
+        let firstDeclaration;
 
         const symbol = type.symbol;
         if (symbol && symbol.declarations) {
@@ -1297,7 +1297,7 @@ namespace ts.refactor.extractSymbol {
         const members = scope.members;
         Debug.assert(members.length > 0); // There must be at least one child, since we extracted from one.
 
-        let prevMember: ClassElement | undefined = undefined;
+        let prevMember: ClassElement | undefined;
         let allProperties = true;
         for (const member of members) {
             if (member.pos > maxPos) {
@@ -1322,7 +1322,7 @@ namespace ts.refactor.extractSymbol {
     function getNodeToInsertConstantBefore(node: Node, scope: Scope): Statement {
         Debug.assert(!isClassLike(scope));
 
-        let prevScope: Scope | undefined = undefined;
+        let prevScope: Scope | undefined;
         for (let curr = node; curr !== scope; curr = curr.parent) {
             if (isScope(curr)) {
                 prevScope = curr;
@@ -1331,7 +1331,7 @@ namespace ts.refactor.extractSymbol {
 
         for (let curr = (prevScope || node).parent; ; curr = curr.parent) {
             if (isBlockLike(curr)) {
-                let prevStatement = undefined;
+                let prevStatement;
                 for (const statement of curr.statements) {
                     if (statement.pos > node.pos) {
                         break;
@@ -1432,7 +1432,7 @@ namespace ts.refactor.extractSymbol {
         const visibleDeclarationsInExtractedRange: NamedDeclaration[] = [];
         const exposedVariableSymbolSet = createMap<true>(); // Key is symbol ID
         const exposedVariableDeclarations: VariableDeclaration[] = [];
-        let firstExposedNonVariableDeclaration: NamedDeclaration | undefined = undefined;
+        let firstExposedNonVariableDeclaration: NamedDeclaration | undefined;
 
         const expression = !isReadonlyArray(targetRange.range)
             ? targetRange.range
@@ -1440,7 +1440,7 @@ namespace ts.refactor.extractSymbol {
                 ? (targetRange.range[0] as ExpressionStatement).expression
                 : undefined;
 
-        let expressionDiagnostic: Diagnostic | undefined = undefined;
+        let expressionDiagnostic: Diagnostic | undefined;
         if (expression === undefined) {
             const statements = targetRange.range as ReadonlyArray<Statement>;
             const start = first(statements).getStart();
@@ -1542,7 +1542,7 @@ namespace ts.refactor.extractSymbol {
             }
 
             let hasWrite = false;
-            let readonlyClassPropertyWrite: Declaration | undefined = undefined;
+            let readonlyClassPropertyWrite: Declaration | undefined;
             usagesPerScope[i].usages.forEach(value => {
                 if (value.usage === Usage.Write) {
                     hasWrite = true;
diff --git a/src/services/services.ts b/src/services/services.ts
index 991b6c1060652..43a2b5cec250d 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -1979,7 +1979,7 @@ namespace ts {
                         continue;
                     }
 
-                    let descriptor: TodoCommentDescriptor = undefined;
+                    let descriptor: TodoCommentDescriptor;
                     for (let i = 0; i < descriptors.length; i++) {
                         if (matchArray[i + firstDescriptorCaptureIndex]) {
                             descriptor = descriptors[i];
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 263ac0f4c3bb3..1a7cc97854acd 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -1420,7 +1420,7 @@ namespace ts {
         function suppressTrailing(node: Node) {
             addEmitFlags(node, EmitFlags.NoTrailingComments);
 
-            let lastChild: Node = undefined;
+            let lastChild: Node;
             forEachChild(
                 node,
                 child => (lastChild = child, undefined),
diff --git a/tslint.json b/tslint.json
index bd06724edb8fc..ce2152a8e1f3e 100644
--- a/tslint.json
+++ b/tslint.json
@@ -103,7 +103,6 @@
         "no-object-literal-type-assertion": false,
         "no-shadowed-variable": false,
         "no-submodule-imports": false,
-        "no-unnecessary-initializer": false,
         "no-var-requires": false,
         "ordered-imports": false,
         "prefer-conditional-expression": false,

From 06cc81155ab521f153455a0b19aefa00ccfc572a Mon Sep 17 00:00:00 2001
From: Josh Goldberg <josh@fullscreenmario.com>
Date: Sat, 17 Feb 2018 13:58:16 -0500
Subject: [PATCH 2/2] Moved worker.ts type assertions to parameters

---
 src/harness/parallel/worker.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/harness/parallel/worker.ts b/src/harness/parallel/worker.ts
index 00c86d4894c8e..e0194815435f5 100644
--- a/src/harness/parallel/worker.ts
+++ b/src/harness/parallel/worker.ts
@@ -54,7 +54,7 @@ namespace Harness.Parallel.Worker {
         const fakeContext: Mocha.ISuiteCallbackContext = {
             retries() { return this; },
             slow() { return this; },
-            timeout(n) {
+            timeout(n: number) {
                 timeout = n;
                 return this;
             },
@@ -126,7 +126,7 @@ namespace Harness.Parallel.Worker {
         let timeout: number;
         const fakeContext: Mocha.ITestCallbackContext = {
             skip() { return this; },
-            timeout(n) {
+            timeout(n: number) {
                 timeout = n;
                 const timeoutMsg: ParallelTimeoutChangeMessage = { type: "timeout", payload: { duration: timeout } };
                 process.send(timeoutMsg);