Add code fix to convert 'require' in a '.ts' file to an 'import'

src/compiler/diagnosticMessages.json

@@ -3898,6 +3898,10 @@
         "category": "Suggestion",
         "code": 80004
     },
+    "'require' call may be converted to an import.": {
+        "category": "Suggestion",
+        "code": 80005
+    },
 
     "Add missing 'super()' call": {
         "category": "Message",
@@ -4174,5 +4178,13 @@
     "Generate 'get' and 'set' accessors": {
         "category": "Message",
         "code": 95046
+    },
+    "Convert 'require' to 'import'": {
+        "category": "Message",
+        "code": 95047
+    },
+    "Convert all 'require' to 'import'": {
+        "category": "Message",
+        "code": 95048
     }
 }

src/harness/fourslash.ts

@@ -324,8 +324,10 @@ namespace FourSlash {
                         this.languageServiceAdapterHost.addScript(fileName, file, /*isRootFile*/ true);
                     }
                 });
-                this.languageServiceAdapterHost.addScript(Harness.Compiler.defaultLibFileName,
-                    Harness.Compiler.getDefaultLibrarySourceFile().text, /*isRootFile*/ false);
+                if (!compilationOptions.noLib) {
+                    this.languageServiceAdapterHost.addScript(Harness.Compiler.defaultLibFileName,
+                        Harness.Compiler.getDefaultLibrarySourceFile().text, /*isRootFile*/ false);
+                }
             }
 
             for (const file of testData.files) {

src/harness/tsconfig.json

@@ -112,6 +112,7 @@
         "../services/codefixes/inferFromUsage.ts",
         "../services/codefixes/fixInvalidImportSyntax.ts",
         "../services/codefixes/fixStrictClassInitialization.ts",
+        "../services/codefixes/requireInTs.ts",
         "../services/codefixes/useDefaultImport.ts",
         "../services/refactors/extractSymbol.ts",
         "../services/refactors/generateGetAccessorAndSetAccessor.ts",

src/server/tsconfig.json

@@ -108,6 +108,7 @@
         "../services/codefixes/inferFromUsage.ts",
         "../services/codefixes/fixInvalidImportSyntax.ts",
         "../services/codefixes/fixStrictClassInitialization.ts",
+        "../services/codefixes/requireInTs.ts",
         "../services/codefixes/useDefaultImport.ts",
         "../services/refactors/extractSymbol.ts",
         "../services/refactors/generateGetAccessorAndSetAccessor.ts",

src/server/tsconfig.library.json

@@ -114,6 +114,7 @@
         "../services/codefixes/inferFromUsage.ts",
         "../services/codefixes/fixInvalidImportSyntax.ts",
         "../services/codefixes/fixStrictClassInitialization.ts",
+        "../services/codefixes/requireInTs.ts",
         "../services/codefixes/useDefaultImport.ts",
         "../services/refactors/extractSymbol.ts",
         "../services/refactors/generateGetAccessorAndSetAccessor.ts",

src/services/codefixes/requireInTs.ts

@@ -0,0 +1,29 @@
+/* @internal */
+namespace ts.codefix {
+    const fixId = "requireInTs";
+    const errorCodes = [Diagnostics.require_call_may_be_converted_to_an_import.code];
+    registerCodeFix({
+        errorCodes,
+        getCodeActions(context) {
+            const changes = textChanges.ChangeTracker.with(context, t => doChange(t, context.sourceFile, context.span.start, context.program));
+            return [createCodeFixAction(fixId, changes, Diagnostics.Convert_require_to_import, fixId, Diagnostics.Convert_all_require_to_import)];
+        },
+        fixIds: [fixId],
+        getAllCodeActions: context => codeFixAll(context, errorCodes, (changes, diag) => doChange(changes, diag.file, diag.start, context.program)),
+    });
+
+    function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, pos: number, program: Program) {
+        const { statement, name, required } = getInfo(sourceFile, pos);
+        changes.replaceNode(sourceFile, statement, getAllowSyntheticDefaultImports(program.getCompilerOptions())
+            ? createImportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, createImportClause(name, /*namedBindings*/ undefined), required)
+            : createImportEqualsDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, name, createExternalModuleReference(required)));
+    }
+
+    interface Info { readonly statement: VariableStatement; readonly name: Identifier; readonly required: StringLiteralLike; }
+    function getInfo(sourceFile: SourceFile, pos: number): Info {
+        const { parent } = getTokenAtPosition(sourceFile, pos, /*includeJsDocComment*/ false);
+        if (!isRequireCall(parent, /*checkArgumentIsStringLiteralLike*/ true)) throw Debug.failBadSyntaxKind(parent);
+        const decl = cast(parent.parent, isVariableDeclaration);
+        return { statement: cast(decl.parent.parent, isVariableStatement), name: cast(decl.name, isIdentifier), required: parent.arguments[0] };
+    }
+}

src/services/suggestionDiagnostics.ts

@@ -32,6 +32,19 @@ namespace ts {
         }
         check(sourceFile);
 
+        if (!isJsFile) {
+            for (const statement of sourceFile.statements) {
+                if (isVariableStatement(statement) &&
+                    statement.declarationList.flags & NodeFlags.Const &&
+                    statement.declarationList.declarations.length === 1) {
+                    const init = statement.declarationList.declarations[0].initializer;
+                    if (init && isRequireCall(init, /*checkArgumentIsStringLiteralLike*/ true)) {
+                        diags.push(createDiagnosticForNode(init, Diagnostics.require_call_may_be_converted_to_an_import));
+                    }
+                }
+            }
+        }
+
         if (getAllowSyntheticDefaultImports(program.getCompilerOptions())) {
             for (const moduleSpecifier of sourceFile.imports) {
                 const importNode = importFromModuleSpecifier(moduleSpecifier);

src/services/tsconfig.json

@@ -105,6 +105,7 @@
         "codefixes/inferFromUsage.ts",
         "codefixes/fixInvalidImportSyntax.ts",
         "codefixes/fixStrictClassInitialization.ts",
+        "codefixes/requireInTs.ts",
         "codefixes/useDefaultImport.ts",
         "refactors/extractSymbol.ts",
         "refactors/generateGetAccessorAndSetAccessor.ts",

tests/cases/fourslash/codeFixRequireInTs.ts

@@ -0,0 +1,15 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////const a = [|require("a")|];
+
+verify.getSuggestionDiagnostics([{
+    message: "'require' call may be converted to an import.",
+    code: 80005,
+}]);
+
+verify.codeFix({
+    description: "Convert 'require' to 'import'",
+    newFileContent:
+`import a = require("a");`,
+});

tests/cases/fourslash/codeFixRequireInTs_all.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////const a = [|require("a")|];
+////const b = [|require("b")|];
+
+verify.codeFixAll({
+    fixId: "requireInTs",
+    fixAllDescription: "Convert all 'require' to 'import'",
+    newFileContent:
+`import a = require("a");
+import b = require("b");`,
+});

tests/cases/fourslash/codeFixRequireInTs_allowSyntheticDefaultImports.ts

@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+// @allowSyntheticDefaultImports: true
+
+// @Filename: /a.ts
+////const a = [|require("a")|];
+
+verify.codeFix({
+    description: "Convert 'require' to 'import'",
+    newFileContent: `import a from "a";`,
+});