Code fix for missing imports

src/compiler/checker.ts

@@ -104,10 +104,10 @@ namespace ts {
             getEmitResolver,
             getExportsOfModule: getExportsOfModuleAsArray,
             getAmbientModules,
-
             getJsxElementAttributesType,
             getJsxIntrinsicTagNames,
             isOptionalParameter,
+            tryGetMemberInModuleExports,
             tryFindAmbientModuleWithoutAugmentations: moduleName => {
                 // we deliberately exclude augmentations
                 // since we are only interested in declarations of the module itself
@@ -1483,6 +1483,13 @@ namespace ts {
             return symbolsToArray(getExportsOfModule(moduleSymbol));
         }
 
+        function tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined {
+            const symbolTable = getExportsOfModule(moduleSymbol);
+            if (symbolTable) {
+                return symbolTable[memberName];
+            }
+        }
+
         function getExportsOfSymbol(symbol: Symbol): SymbolTable {
             return symbol.flags & SymbolFlags.Module ? getExportsOfModule(symbol) : symbol.exports || emptySymbols;
         }

src/compiler/core.ts

@@ -1374,6 +1374,14 @@ namespace ts {
             getEmitScriptTarget(compilerOptions) >= ScriptTarget.ES2015 ? ModuleKind.ES2015 : ModuleKind.CommonJS;
     }
 
+    export function getEmitModuleResolutionKind(compilerOptions: CompilerOptions) {
+        let moduleResolution = compilerOptions.moduleResolution;
+        if (moduleResolution === undefined) {
+            moduleResolution = getEmitModuleKind(compilerOptions) === ModuleKind.CommonJS ? ModuleResolutionKind.NodeJs : ModuleResolutionKind.Classic;
+        }
+        return moduleResolution;
+    }
+
     /* @internal */
     export function hasZeroOrOneAsteriskCharacter(str: string): boolean {
         let seenAsterisk = false;

src/compiler/diagnosticMessages.json

@@ -3190,5 +3190,17 @@
     "Type '{0}' is not assignable to type '{1}'. Two different types with this name exist, but they are unrelated.": {
         "category": "Error",
         "code": 90010
+    },
+    "Import {0} from {1}": {
+        "category": "Message",
+        "code": 90013
+    },
+    "Change {0} to {1}": {
+        "category": "Message",
+        "code": 90014
+    },
+    "Add {0} to existing import declaration from {1}": {
+        "category": "Message",
+        "code": 90015
     }
 }

src/compiler/moduleNameResolver.ts

@@ -61,7 +61,7 @@ namespace ts {
         return { resolvedModule: resolved && resolvedModuleFromResolved(resolved, isExternalLibraryImport), failedLookupLocations };
     }
 
-    function moduleHasNonRelativeName(moduleName: string): boolean {
+    export function moduleHasNonRelativeName(moduleName: string): boolean {
         return !(isRootedDiskPath(moduleName) || isExternalModuleNameRelative(moduleName));
     }
 

src/compiler/types.ts

@@ -2314,6 +2314,8 @@ namespace ts {
         isOptionalParameter(node: ParameterDeclaration): boolean;
         getAmbientModules(): Symbol[];
 
+        tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
+
         /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol;
 
         // Should not be called directly.  Should only be accessed through the Program instance.
@@ -3133,7 +3135,7 @@ namespace ts {
         target?: ScriptTarget;
         traceResolution?: boolean;
         types?: string[];
-        /** Paths used to used to compute primary types search locations */
+        /** Paths used to compute primary types search locations */
         typeRoots?: string[];
         /*@internal*/ version?: boolean;
         /*@internal*/ watch?: boolean;

src/harness/fourslash.ts

@@ -2046,6 +2046,34 @@ namespace FourSlash {
             }
         }
 
+        public verifyImportFixAtPosition(expectedTextArray: string[], errorCode?: number) {
+            const ranges = this.getRanges();
+            if (ranges.length == 0) {
+                this.raiseError("At least one range should be specified in the testfile.");
+            }
+
+            const codeFixes = this.getCodeFixes(errorCode);
+
+            if (!codeFixes || codeFixes.length == 0) {
+                this.raiseError("No codefixes returned.");
+            }
+
+            const actualTextArray: string[] = [];
+            const scriptInfo = this.languageServiceAdapterHost.getScriptInfo(codeFixes[0].changes[0].fileName);
+            const originalContent = scriptInfo.content;
+            for (const codeFix of codeFixes) {
+                this.applyEdits(codeFix.changes[0].fileName, codeFix.changes[0].textChanges, /*isFormattingEdit*/ false);
+                actualTextArray.push(this.normalizeNewlines(this.rangeText(ranges[0])));
+                scriptInfo.updateContent(originalContent);
+            }
+            const sortedExpectedArray = ts.map(expectedTextArray, str => this.normalizeNewlines(str)).sort();
+            const sortedActualArray = actualTextArray.sort();
+            if (!ts.arrayIsEqualTo(sortedExpectedArray, sortedActualArray)) {
+                this.raiseError(
+                    `Actual text array doesn't match expected text array. \nActual: \n"${sortedActualArray.join("\n\n")}"\n---\nExpected: \n'${sortedExpectedArray.join("\n\n")}'`);
+            }
+        }
+
         public verifyDocCommentTemplate(expected?: ts.TextInsertion) {
             const name = "verifyDocCommentTemplate";
             const actual = this.languageService.getDocCommentTemplateAtPosition(this.activeFile.fileName, this.currentCaretPosition);
@@ -2079,6 +2107,10 @@ namespace FourSlash {
             });
         }
 
+        private normalizeNewlines(str: string) {
+            return str.replace(/\r?\n/g, "\n");
+        }
+
         public verifyBraceCompletionAtPosition(negative: boolean, openingBrace: string) {
 
             const openBraceMap = ts.createMap<ts.CharacterCodes>({
@@ -2606,7 +2638,7 @@ ${code}
                                 resetLocalData();
                             }
 
-                            currentFileName = basePath + "/" + value;
+                            currentFileName = ts.isRootedDiskPath(value) ? value : basePath + "/" + value;
                             currentFileOptions[key] = value;
                         }
                         else {
@@ -3303,6 +3335,10 @@ namespace FourSlashInterface {
             this.state.verifyCodeFixAtPosition(expectedText, errorCode);
         }
 
+        public importFixAtPosition(expectedTextArray: string[], errorCode?: number): void {
+            this.state.verifyImportFixAtPosition(expectedTextArray, errorCode);
+        }
+
         public navigationBar(json: any) {
             this.state.verifyNavigationBar(json);
         }

src/services/codefixes/codeFixProvider.ts

@@ -1,4 +1,4 @@
-/* @internal */
+/* @internal */
 namespace ts {
     export interface CodeFix {
         errorCodes: number[];
@@ -11,6 +11,8 @@ namespace ts {
         span: TextSpan;
         program: Program;
         newLineCharacter: string;
+        host: LanguageServiceHost;
+        cancellationToken: CancellationToken;
     }
 
     export namespace codefix {

src/services/codefixes/fixes.ts

@@ -1,2 +1,3 @@
 ///<reference path='superFixes.ts' />
-///<reference path='unusedIdentifierFixes.ts' />
+///<reference path='importFixes.ts' />
+///<reference path='unusedIdentifierFixes.ts' />