add missing index signature support

Author: Arthur Ozga

src/services/codefixes/fixClassIncorrectlyImplementsInterface.ts

@@ -14,19 +14,37 @@ namespace ts.codefix {
             }
 
             const startPos: number = classDecl.members.pos;
-
+            const classType = checker.getTypeAtLocation(classDecl);
             const implementedTypeNodes = getClassImplementsHeritageClauseElements(classDecl);
-
             const result: CodeAction[] = [];
 
+            const hasNumericIndexSignature = !!checker.getIndexTypeOfType(classType, IndexKind.Number);
+            const hasStringIndexSignature = !!checker.getIndexTypeOfType(classType, IndexKind.String);
+
             for (const implementedTypeNode of implementedTypeNodes) {
-                const implementedType = checker.getTypeFromTypeReference(implementedTypeNode);
+                const implementedType = checker.getTypeFromTypeReference(implementedTypeNode) as InterfaceTypeWithDeclaredMembers;
                 // Note that this is ultimately derived from a map indexed by symbol names,
                 // so duplicates cannot occur.
                 const implementedTypeSymbols = checker.getPropertiesOfType(implementedType);
                 const nonPrivateMembers = implementedTypeSymbols.filter(symbolRefersToNonPrivateMember);
 
-                const insertion = getMissingMembersInsertion(classDecl, nonPrivateMembers, checker, context.newLineCharacter);
+                let insertion = "";
+
+                if (!hasNumericIndexSignature) {
+                    const typeNumericIndexInfo = implementedType.declaredNumberIndexInfo;
+                    if (typeNumericIndexInfo) {
+                        insertion = checker.indexSignatureToString(typeNumericIndexInfo, SyntaxKind.NumberKeyword, classDecl);
+                    }
+                }
+
+                if (!hasStringIndexSignature) {
+                    const typeStringIndexInfo = implementedType.declaredStringIndexInfo;
+                    if (typeStringIndexInfo) {
+                        insertion += checker.indexSignatureToString(typeStringIndexInfo, SyntaxKind.StringKeyword, classDecl);
+                    }
+                }
+
+                insertion += getMissingMembersInsertion(classDecl, nonPrivateMembers, checker, context.newLineCharacter);
                 const message = formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Implement_interface_0), [implementedTypeNode.getText()]);
                 if (insertion) {
                     pushAction(result, insertion, message);

src/services/codefixes/helpers.ts

@@ -5,7 +5,7 @@ namespace ts.codefix {
      * Finds members of the resolved type that are missing in the class pointed to by class decl
      * and generates source code for the missing members.
      * @param possiblyMissingSymbols The collection of symbols to filter and then get insertions for.
-     * @returns undefined iff there is no insertion available.
+     * @returns Empty string iff there are no member insertions.
      */
     export function getMissingMembersInsertion(classDeclaration: ClassLikeDeclaration, possiblyMissingSymbols: Symbol[], checker: TypeChecker, newlineChar: string): string {
         const classMembers = classDeclaration.symbol.members;
@@ -16,9 +16,12 @@ namespace ts.codefix {
         for (const symbol of missingMembers) {
             insertion = insertion.concat(getInsertionForMemberSymbol(symbol, classDeclaration, checker, newlineChar));
         }
-        return insertion.length > 0 ? insertion : undefined;
+        return insertion;
     }
 
+    /**
+     * @returns Empty string iff there we can't figure out a representation for `symbol` in `enclosingDeclaration`.
+     */
     function getInsertionForMemberSymbol(symbol: Symbol, enclosingDeclaration: ClassLikeDeclaration, checker: TypeChecker, newlineChar: string): string {
         // const name = symbol.getName();
         const type = checker.getTypeOfSymbolAtLocation(symbol, enclosingDeclaration);
@@ -28,8 +31,9 @@ namespace ts.codefix {
         }
 
         const declaration = declarations[0] as Declaration;
-        const name = declaration.name.getText();
+        const name = declaration.name ? declaration.name.getText() : undefined;
         const visibility = getVisibilityPrefix(getModifierFlags(declaration));
+
         switch (declaration.kind) {
             case SyntaxKind.GetAccessor:
             case SyntaxKind.SetAccessor:
@@ -77,14 +81,6 @@ namespace ts.codefix {
                 result += `${visibility}${name}${sigString}${getMethodBodyStub(newlineChar)}`;
 
                 return result;
-            case SyntaxKind.ComputedPropertyName:
-                if (hasDynamicName(declaration)) {
-                    return "";
-                }
-                throw new Error("Not implemented, computed property name.");
-            case SyntaxKind.IndexSignature:
-                throw new Error("Not implemented.");
-
             default:
                 return "";
         }

tests/cases/fourslash/codeFixUnImplementedInterfaceComputedPropertyLiterals.ts

@@ -6,7 +6,7 @@
 ////     [1](): string;
 ////     [2]: boolean;
 //// }
-
+////
 //// class C implements I {[|  |]}
 
 verify.rangeAfterCodeFix(`

tests/cases/fourslash/codeFixUnImplementedInterfaceIndexSignaturesBoth.ts

@@ -0,0 +1,14 @@
+/// <reference path='fourslash.ts' />
+
+
+//// interface I {
+////     [x: number]: I;
+////     [y: string]: I;
+//// }
+////
+//// class C implements I {[| |]}
+
+verify.rangeAfterCodeFix(`
+    [x: number]: I;
+    [y: string]: I;
+`);

tests/cases/fourslash/codeFixUnImplementedInterfaceIndexSignaturesNoFix.ts

@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+//// interface I4 {
+////     [x: string, y: number]: number;
+//// }
+////
+//// class C implements I {[|  |]}
+
+verify.not.codeFixAvailable();
+
+

tests/cases/fourslash/codeFixUnImplementedInterfaceIndexSignaturesNumber.ts

@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts' />
+
+//// interface I {
+////     [x: number]: I;
+//// }
+////
+//// class C implements I {[|
+//// |]}
+
+verify.rangeAfterCodeFix(`
+    [x: number]: I;
+`);

tests/cases/fourslash/codeFixUnImplementedInterfaceIndexSignaturesString.ts

@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+//// interface I {
+////     [x: string]: number;
+//// }
+////
+//// class C implements I {[| |]}
+
+verify.rangeAfterCodeFix(`
+    [x: string]: number;
+`);