Add helper functions for detecting 'this' identifiers

Andy Hanson · Andy Hanson · commit 1879e28fd317 · 2016-10-05T08:54:20.000-07:00
diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
@@ -2432,8 +2432,7 @@ namespace ts {
         }
 
         // If the parameter's name is 'this', then it is TypeScript syntax.
-        if (subtreeFlags & TransformFlags.ContainsDecorators
-            || (name && isIdentifier(name) && name.originalKeywordKind === SyntaxKind.ThisKeyword)) {
+        if (subtreeFlags & TransformFlags.ContainsDecorators || isThisIdentifier(name)) {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -9373,7 +9373,7 @@ namespace ts {
                 captureLexicalThis(node, container);
             }
             if (isFunctionLike(container) &&
-                (!isInParameterInitializerBeforeContainingFunction(node) || getFunctionLikeThisParameter(container))) {
+                (!isInParameterInitializerBeforeContainingFunction(node) || getThisParameter(container))) {
                 // Note: a parameter initializer should refer to class-this unless function-this is explicitly annotated.
 
                 // If this is a function in a JS file, it might be a class method. Check if it's the RHS
@@ -15557,10 +15557,6 @@ namespace ts {
             }
         }
 
-        function parameterIsThisKeyword(parameter: ParameterDeclaration) {
-            return parameter.name && (<Identifier>parameter.name).originalKeywordKind === SyntaxKind.ThisKeyword;
-        }
-
         function parameterNameStartsWithUnderscore(parameter: ParameterDeclaration) {
             return parameter.name && parameter.name.kind === SyntaxKind.Identifier && (<Identifier>parameter.name).text.charCodeAt(0) === CharacterCodes._;
         }
@@ -20141,18 +20137,8 @@ namespace ts {
         }
 
         function getAccessorThisParameter(accessor: AccessorDeclaration): ParameterDeclaration {
-            if (accessor.parameters.length === (accessor.kind === SyntaxKind.GetAccessor ? 1 : 2) &&
-                accessor.parameters[0].name.kind === SyntaxKind.Identifier &&
-                (<Identifier>accessor.parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword) {
-                return accessor.parameters[0];
-            }
-        }
-
-        function getFunctionLikeThisParameter(func: FunctionLikeDeclaration) {
-            if (func.parameters.length &&
-                func.parameters[0].name.kind === SyntaxKind.Identifier &&
-                (<Identifier>func.parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword) {
-                return func.parameters[0];
+            if (accessor.parameters.length === (accessor.kind === SyntaxKind.GetAccessor ? 1 : 2)) {
+                return getThisParameter(accessor);
             }
         }
 
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
@@ -2374,7 +2374,7 @@ namespace ts {
          * @param node The parameter declaration node.
          */
         function visitParameter(node: ParameterDeclaration) {
-            if (node.name && isIdentifier(node.name) && node.name.originalKeywordKind === SyntaxKind.ThisKeyword) {
+            if (parameterIsThisKeyword(node)) {
                 return undefined;
             }
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
@@ -2707,15 +2707,35 @@ namespace ts {
         });
     }
 
-    export function getSetAccessorTypeAnnotationNode(accessor: AccessorDeclaration): TypeNode {
+    /** Get the type annotaion for the value parameter. */
+    export function getSetAccessorTypeAnnotationNode(accessor: SetAccessorDeclaration): TypeNode {
         if (accessor && accessor.parameters.length > 0) {
-            const hasThis = accessor.parameters.length === 2 &&
-                accessor.parameters[0].name.kind === SyntaxKind.Identifier &&
-                (accessor.parameters[0].name as Identifier).originalKeywordKind === SyntaxKind.ThisKeyword;
+            const hasThis = accessor.parameters.length === 2 && parameterIsThisKeyword(accessor.parameters[0]);
             return accessor.parameters[hasThis ? 1 : 0].type;
         }
     }
 
+    export function getThisParameter(signature: SignatureDeclaration): ParameterDeclaration | undefined {
+        if (signature.parameters.length) {
+            const thisParameter = signature.parameters[0];
+            if (parameterIsThisKeyword(thisParameter)) {
+                return thisParameter;
+            }
+        }
+    }
+
+    export function parameterIsThisKeyword(parameter: ParameterDeclaration): boolean {
+        return isThisIdentifier(parameter.name);
+    }
+
+    export function isThisIdentifier(node: Node | undefined): boolean {
+        return node && node.kind === SyntaxKind.Identifier && identifierIsThisKeyword(node as Identifier);
+    }
+
+    export function identifierIsThisKeyword(id: Identifier): boolean {
+        return id.originalKeywordKind === SyntaxKind.ThisKeyword;
+    }
+
     export interface AllAccessorDeclarations {
         firstAccessor: AccessorDeclaration;
         secondAccessor: AccessorDeclaration;
diff --git a/src/services/classifier.ts b/src/services/classifier.ts
@@ -954,8 +954,7 @@ namespace ts {
                             return;
                         case SyntaxKind.Parameter:
                             if ((<ParameterDeclaration>token.parent).name === token) {
-                                const isThis = token.kind === SyntaxKind.Identifier && (<Identifier>token).originalKeywordKind === SyntaxKind.ThisKeyword;
-                                return isThis ? ClassificationType.keyword : ClassificationType.parameterName;
+                                return isThisIdentifier(token) ? ClassificationType.keyword : ClassificationType.parameterName;
                             }
                             return;
                     }
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
@@ -376,7 +376,7 @@ namespace ts {
                 return true;
             case SyntaxKind.Identifier:
                 // 'this' as a parameter
-                return (node as Identifier).originalKeywordKind === SyntaxKind.ThisKeyword && node.parent.kind === SyntaxKind.Parameter;
+                return identifierIsThisKeyword(node as Identifier) && node.parent.kind === SyntaxKind.Parameter;
             default:
                 return false;
         }

Original file line number	Diff line number	Diff line change
`@@ -2432,8 +2432,7 @@ namespace ts {`
`2432`	`2432`	`}`
`2433`	`2433`
`2434`	`2434`	`// If the parameter's name is 'this', then it is TypeScript syntax.`
`2435`		`- if (subtreeFlags & TransformFlags.ContainsDecorators`
`2436`		`- \|\| (name && isIdentifier(name) && name.originalKeywordKind === SyntaxKind.ThisKeyword)) {`
	`2435`	`+ if (subtreeFlags & TransformFlags.ContainsDecorators \|\| isThisIdentifier(name)) {`
`2437`	`2436`	`transformFlags \|= TransformFlags.AssertTypeScript;`
`2438`	`2437`	`}`
`2439`	`2438`
Original file line number	Diff line number	Diff line change
`@@ -9373,7 +9373,7 @@ namespace ts {`
`9373`	`9373`	`captureLexicalThis(node, container);`
`9374`	`9374`	`}`
`9375`	`9375`	`if (isFunctionLike(container) &&`
`9376`		`- (!isInParameterInitializerBeforeContainingFunction(node) \|\| getFunctionLikeThisParameter(container))) {`
	`9376`	`+ (!isInParameterInitializerBeforeContainingFunction(node) \|\| getThisParameter(container))) {`
`9377`	`9377`	`// Note: a parameter initializer should refer to class-this unless function-this is explicitly annotated.`
`9378`	`9378`
`9379`	`9379`	`// If this is a function in a JS file, it might be a class method. Check if it's the RHS`
`@@ -15557,10 +15557,6 @@ namespace ts {`
`15557`	`15557`	`}`
`15558`	`15558`	`}`
`15559`	`15559`
`15560`		`- function parameterIsThisKeyword(parameter: ParameterDeclaration) {`
`15561`		`- return parameter.name && (<Identifier>parameter.name).originalKeywordKind === SyntaxKind.ThisKeyword;`
`15562`		`- }`
`15563`		`-`
`15564`	`15560`	`function parameterNameStartsWithUnderscore(parameter: ParameterDeclaration) {`
`15565`	`15561`	`return parameter.name && parameter.name.kind === SyntaxKind.Identifier && (<Identifier>parameter.name).text.charCodeAt(0) === CharacterCodes._;`
`15566`	`15562`	`}`
`@@ -20141,18 +20137,8 @@ namespace ts {`
`20141`	`20137`	`}`
`20142`	`20138`
`20143`	`20139`	`function getAccessorThisParameter(accessor: AccessorDeclaration): ParameterDeclaration {`
`20144`		`- if (accessor.parameters.length === (accessor.kind === SyntaxKind.GetAccessor ? 1 : 2) &&`
`20145`		`- accessor.parameters[0].name.kind === SyntaxKind.Identifier &&`
`20146`		`- (<Identifier>accessor.parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword) {`
`20147`		`- return accessor.parameters[0];`
`20148`		`- }`
`20149`		`- }`
`20150`		`-`
`20151`		`- function getFunctionLikeThisParameter(func: FunctionLikeDeclaration) {`
`20152`		`- if (func.parameters.length &&`
`20153`		`- func.parameters[0].name.kind === SyntaxKind.Identifier &&`
`20154`		`- (<Identifier>func.parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword) {`
`20155`		`- return func.parameters[0];`
	`20140`	`+ if (accessor.parameters.length === (accessor.kind === SyntaxKind.GetAccessor ? 1 : 2)) {`
	`20141`	`+ return getThisParameter(accessor);`
`20156`	`20142`	`}`
`20157`	`20143`	`}`
`20158`	`20144`
Original file line number	Diff line number	Diff line change
`@@ -2374,7 +2374,7 @@ namespace ts {`
`2374`	`2374`	`* @param node The parameter declaration node.`
`2375`	`2375`	`*/`
`2376`	`2376`	`function visitParameter(node: ParameterDeclaration) {`
`2377`		`- if (node.name && isIdentifier(node.name) && node.name.originalKeywordKind === SyntaxKind.ThisKeyword) {`
	`2377`	`+ if (parameterIsThisKeyword(node)) {`
`2378`	`2378`	`return undefined;`
`2379`	`2379`	`}`
`2380`	`2380`
Original file line number	Diff line number	Diff line change
`@@ -954,8 +954,7 @@ namespace ts {`
`954`	`954`	`return;`
`955`	`955`	`case SyntaxKind.Parameter:`
`956`	`956`	`if ((<ParameterDeclaration>token.parent).name === token) {`
`957`		`- const isThis = token.kind === SyntaxKind.Identifier && (<Identifier>token).originalKeywordKind === SyntaxKind.ThisKeyword;`
`958`		`- return isThis ? ClassificationType.keyword : ClassificationType.parameterName;`
	`957`	`+ return isThisIdentifier(token) ? ClassificationType.keyword : ClassificationType.parameterName;`
`959`	`958`	`}`
`960`	`959`	`return;`
`961`	`960`	`}`
Original file line number	Diff line number	Diff line change
`@@ -376,7 +376,7 @@ namespace ts {`
`376`	`376`	`return true;`
`377`	`377`	`case SyntaxKind.Identifier:`
`378`	`378`	`// 'this' as a parameter`
`379`		`- return (node as Identifier).originalKeywordKind === SyntaxKind.ThisKeyword && node.parent.kind === SyntaxKind.Parameter;`
	`379`	`+ return identifierIsThisKeyword(node as Identifier) && node.parent.kind === SyntaxKind.Parameter;`
`380`	`380`	`default:`
`381`	`381`	`return false;`
`382`	`382`	`}`