Allow both module.exports= and module.exports property assignments

src/compiler/checker.ts

@@ -2216,7 +2216,22 @@ namespace ts {
         // An external module with an 'export =' declaration resolves to the target of the 'export =' declaration,
         // and an external module with no 'export =' declaration resolves to the module itself.
         function resolveExternalModuleSymbol(moduleSymbol: Symbol, dontResolveAlias?: boolean): Symbol {
-            return moduleSymbol && getMergedSymbol(resolveSymbol(moduleSymbol.exports.get(InternalSymbolName.ExportEquals), dontResolveAlias)) || moduleSymbol;
+            return moduleSymbol && getMergedSymbol(resolveSymbol(getCommonJsExportEquals(moduleSymbol), dontResolveAlias)) || moduleSymbol;
+        }
+
+        function getCommonJsExportEquals(moduleSymbol: Symbol): Symbol {
+            const exported = moduleSymbol.exports.get(InternalSymbolName.ExportEquals);
+            if (!exported || !exported.exports || moduleSymbol.exports.size === 1) {
+                return exported;
+            }
+            const merged = cloneSymbol(exported);
+            moduleSymbol.exports.forEach((s, name) => {
+                if (name === InternalSymbolName.ExportEquals) return;
+                if (!merged.exports.has(name)) {
+                    merged.exports.set(name, s);
+                }
+            });
+            return merged;
         }
 
         // An external module with an 'export =' declaration may be referenced as an ES6 module provided the 'export ='
@@ -4350,7 +4365,8 @@ namespace ts {
                     return unknownType;
                 }
 
-                if (isPropertyAccessExpression(expression.left) && expression.left.expression.kind === SyntaxKind.ThisKeyword) {
+                const special = getSpecialPropertyAssignmentKind(expression);
+                if (special === SpecialPropertyAssignmentKind.ThisProperty) {
                     const thisContainer = getThisContainer(expression, /*includeArrowFunctions*/ false);
                     // Properties defined in a constructor (or javascript constructor function) don't get undefined added.
                     // Function expressions that are assigned to the prototype count as methods.
@@ -4380,7 +4396,33 @@ namespace ts {
                 }
                 else if (!jsDocType) {
                     // If we don't have an explicit JSDoc type, get the type from the expression.
-                    const type = getWidenedLiteralType(checkExpressionCached(expression.right));
+                    let type = getWidenedLiteralType(checkExpressionCached(expression.right));
+
+                    if (getObjectFlags(type) & ObjectFlags.Anonymous &&
+                        special === SpecialPropertyAssignmentKind.ModuleExports &&
+                        symbol.escapedName === InternalSymbolName.ExportEquals) {
+                        const exportedType = resolveStructuredTypeMembers(type as AnonymousType);
+                        const members = createSymbolTable();
+                        copyEntries(exportedType.members, members);
+                        symbol.exports.forEach((s, name) => {
+                            if (members.has(name)) {
+                                const exportedMember = exportedType.members.get(name);
+                                const union = createSymbol(s.flags | exportedMember.flags, name);
+                                union.type = getUnionType([getTypeOfSymbol(s), getTypeOfSymbol(exportedMember)]);
+                                members.set(name, union);
+                            }
+                            else {
+                                members.set(name, s);
+                            }
+                        });
+                        type = createAnonymousType(
+                            exportedType.symbol,
+                            members,
+                            exportedType.callSignatures,
+                            exportedType.constructSignatures,
+                            exportedType.stringIndexInfo,
+                            exportedType.numberIndexInfo);
+                    }
                     let anyedType = type;
                     if (isEmptyArrayLiteralType(type)) {
                         anyedType = anyArrayType;
@@ -24568,7 +24610,7 @@ namespace ts {
                 const exportEqualsSymbol = moduleSymbol.exports.get("export=" as __String);
                 if (exportEqualsSymbol && hasExportedMembers(moduleSymbol)) {
                     const declaration = getDeclarationOfAliasSymbol(exportEqualsSymbol) || exportEqualsSymbol.valueDeclaration;
-                    if (!isTopLevelInExternalModuleAugmentation(declaration)) {
+                    if (!isTopLevelInExternalModuleAugmentation(declaration) && !isInJavaScriptFile(declaration)) {
                         error(declaration, Diagnostics.An_export_assignment_cannot_be_used_in_a_module_with_other_exported_elements);
                     }
                 }

tests/baselines/reference/moduleExportWithExportPropertyAssignment.errors.txt

@@ -0,0 +1,20 @@
+tests/cases/conformance/salsa/a.js(4,1): error TS2554: Expected 1 arguments, but got 0.
+
+
+==== tests/cases/conformance/salsa/a.js (1 errors) ====
+    /// <reference path='./requires.d.ts' />
+    var mod1 = require('./mod1')
+    mod1()
+    mod1.f() // error, not enough arguments
+    ~~~~~~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+
+==== tests/cases/conformance/salsa/requires.d.ts (0 errors) ====
+    declare var module: { exports: any };
+    declare function require(name: string): any;
+==== tests/cases/conformance/salsa/mod1.js (0 errors) ====
+    /// <reference path='./requires.d.ts' />
+    module.exports = function () { }
+    /** @param {number} a */
+    module.exports.f = function (a) { }
+

tests/baselines/reference/moduleExportWithExportPropertyAssignment.symbols

@@ -0,0 +1,39 @@
+=== tests/cases/conformance/salsa/a.js ===
+/// <reference path='./requires.d.ts' />
+var mod1 = require('./mod1')
+>mod1 : Symbol(mod1, Decl(a.js, 1, 3))
+>require : Symbol(require, Decl(requires.d.ts, 0, 37))
+>'./mod1' : Symbol("tests/cases/conformance/salsa/mod1", Decl(mod1.js, 0, 0))
+
+mod1()
+>mod1 : Symbol(mod1, Decl(a.js, 1, 3))
+
+mod1.f() // error, not enough arguments
+>mod1.f : Symbol(f, Decl(mod1.js, 1, 32))
+>mod1 : Symbol(mod1, Decl(a.js, 1, 3))
+>f : Symbol(f, Decl(mod1.js, 1, 32))
+
+=== tests/cases/conformance/salsa/requires.d.ts ===
+declare var module: { exports: any };
+>module : Symbol(module, Decl(requires.d.ts, 0, 11))
+>exports : Symbol(exports, Decl(requires.d.ts, 0, 21))
+
+declare function require(name: string): any;
+>require : Symbol(require, Decl(requires.d.ts, 0, 37))
+>name : Symbol(name, Decl(requires.d.ts, 1, 25))
+
+=== tests/cases/conformance/salsa/mod1.js ===
+/// <reference path='./requires.d.ts' />
+module.exports = function () { }
+>module.exports : Symbol(exports, Decl(requires.d.ts, 0, 21))
+>module : Symbol(export=, Decl(mod1.js, 0, 0))
+>exports : Symbol(export=, Decl(mod1.js, 0, 0))
+
+/** @param {number} a */
+module.exports.f = function (a) { }
+>module.exports : Symbol(f, Decl(mod1.js, 1, 32))
+>module : Symbol(module, Decl(requires.d.ts, 0, 11))
+>exports : Symbol(exports, Decl(requires.d.ts, 0, 21))
+>f : Symbol(f, Decl(mod1.js, 1, 32))
+>a : Symbol(a, Decl(mod1.js, 3, 29))
+

tests/baselines/reference/moduleExportWithExportPropertyAssignment.types

@@ -0,0 +1,47 @@
+=== tests/cases/conformance/salsa/a.js ===
+/// <reference path='./requires.d.ts' />
+var mod1 = require('./mod1')
+>mod1 : { (): void; f: (a: number) => void; }
+>require('./mod1') : { (): void; f: (a: number) => void; }
+>require : (name: string) => any
+>'./mod1' : "./mod1"
+
+mod1()
+>mod1() : void
+>mod1 : { (): void; f: (a: number) => void; }
+
+mod1.f() // error, not enough arguments
+>mod1.f() : void
+>mod1.f : (a: number) => void
+>mod1 : { (): void; f: (a: number) => void; }
+>f : (a: number) => void
+
+=== tests/cases/conformance/salsa/requires.d.ts ===
+declare var module: { exports: any };
+>module : { exports: any; }
+>exports : any
+
+declare function require(name: string): any;
+>require : (name: string) => any
+>name : string
+
+=== tests/cases/conformance/salsa/mod1.js ===
+/// <reference path='./requires.d.ts' />
+module.exports = function () { }
+>module.exports = function () { } : () => void
+>module.exports : any
+>module : { exports: any; }
+>exports : any
+>function () { } : () => void
+
+/** @param {number} a */
+module.exports.f = function (a) { }
+>module.exports.f = function (a) { } : (a: number) => void
+>module.exports.f : any
+>module.exports : any
+>module : { exports: any; }
+>exports : any
+>f : any
+>function (a) { } : (a: number) => void
+>a : number
+

tests/baselines/reference/moduleExportWithExportPropertyAssignment2.errors.txt

@@ -0,0 +1,19 @@
+tests/cases/conformance/salsa/a.js(4,6): error TS2339: Property 'f' does not exist on type 'number'.
+
+
+==== tests/cases/conformance/salsa/a.js (1 errors) ====
+    /// <reference path='./requires.d.ts' />
+    var mod1 = require('./mod1')
+    mod1.toFixed(12)
+    mod1.f() // error, 'f' is not a property on 'number'
+         ~
+!!! error TS2339: Property 'f' does not exist on type 'number'.
+
+==== tests/cases/conformance/salsa/requires.d.ts (0 errors) ====
+    declare var module: { exports: any };
+    declare function require(name: string): any;
+==== tests/cases/conformance/salsa/mod1.js (0 errors) ====
+    /// <reference path='./requires.d.ts' />
+    module.exports = 1
+    module.exports.f = function () { }
+

tests/baselines/reference/moduleExportWithExportPropertyAssignment2.symbols

@@ -0,0 +1,37 @@
+=== tests/cases/conformance/salsa/a.js ===
+/// <reference path='./requires.d.ts' />
+var mod1 = require('./mod1')
+>mod1 : Symbol(mod1, Decl(a.js, 1, 3))
+>require : Symbol(require, Decl(requires.d.ts, 0, 37))
+>'./mod1' : Symbol("tests/cases/conformance/salsa/mod1", Decl(mod1.js, 0, 0))
+
+mod1.toFixed(12)
+>mod1.toFixed : Symbol(Number.toFixed, Decl(lib.d.ts, --, --))
+>mod1 : Symbol(mod1, Decl(a.js, 1, 3))
+>toFixed : Symbol(Number.toFixed, Decl(lib.d.ts, --, --))
+
+mod1.f() // error, 'f' is not a property on 'number'
+>mod1 : Symbol(mod1, Decl(a.js, 1, 3))
+
+=== tests/cases/conformance/salsa/requires.d.ts ===
+declare var module: { exports: any };
+>module : Symbol(module, Decl(requires.d.ts, 0, 11))
+>exports : Symbol(exports, Decl(requires.d.ts, 0, 21))
+
+declare function require(name: string): any;
+>require : Symbol(require, Decl(requires.d.ts, 0, 37))
+>name : Symbol(name, Decl(requires.d.ts, 1, 25))
+
+=== tests/cases/conformance/salsa/mod1.js ===
+/// <reference path='./requires.d.ts' />
+module.exports = 1
+>module.exports : Symbol(exports, Decl(requires.d.ts, 0, 21))
+>module : Symbol(export=, Decl(mod1.js, 0, 0))
+>exports : Symbol(export=, Decl(mod1.js, 0, 0))
+
+module.exports.f = function () { }
+>module.exports : Symbol(f, Decl(mod1.js, 1, 18))
+>module : Symbol(module, Decl(requires.d.ts, 0, 11))
+>exports : Symbol(exports, Decl(requires.d.ts, 0, 21))
+>f : Symbol(f, Decl(mod1.js, 1, 18))
+

tests/baselines/reference/moduleExportWithExportPropertyAssignment2.types

@@ -0,0 +1,48 @@
+=== tests/cases/conformance/salsa/a.js ===
+/// <reference path='./requires.d.ts' />
+var mod1 = require('./mod1')
+>mod1 : number
+>require('./mod1') : number
+>require : (name: string) => any
+>'./mod1' : "./mod1"
+
+mod1.toFixed(12)
+>mod1.toFixed(12) : string
+>mod1.toFixed : (fractionDigits?: number) => string
+>mod1 : number
+>toFixed : (fractionDigits?: number) => string
+>12 : 12
+
+mod1.f() // error, 'f' is not a property on 'number'
+>mod1.f() : any
+>mod1.f : any
+>mod1 : number
+>f : any
+
+=== tests/cases/conformance/salsa/requires.d.ts ===
+declare var module: { exports: any };
+>module : { exports: any; }
+>exports : any
+
+declare function require(name: string): any;
+>require : (name: string) => any
+>name : string
+
+=== tests/cases/conformance/salsa/mod1.js ===
+/// <reference path='./requires.d.ts' />
+module.exports = 1
+>module.exports = 1 : 1
+>module.exports : any
+>module : { exports: any; }
+>exports : any
+>1 : 1
+
+module.exports.f = function () { }
+>module.exports.f = function () { } : () => void
+>module.exports.f : any
+>module.exports : any
+>module : { exports: any; }
+>exports : any
+>f : any
+>function () { } : () => void
+

tests/baselines/reference/moduleExportWithExportPropertyAssignment3.errors.txt

@@ -0,0 +1,34 @@
+tests/cases/conformance/salsa/a.js(4,17): error TS2339: Property 'toFixed' does not exist on type 'string | number'.
+  Property 'toFixed' does not exist on type 'string'.
+tests/cases/conformance/salsa/a.js(5,16): error TS2339: Property 'toFixed' does not exist on type 'string | number'.
+  Property 'toFixed' does not exist on type 'string'.
+
+
+==== tests/cases/conformance/salsa/a.js (2 errors) ====
+    /// <reference path='./requires.d.ts' />
+    var mod1 = require('./mod1')
+    mod1.justExport.toFixed()
+    mod1.bothBefore.toFixed() // error, 'toFixed' not on 'string | number'
+                    ~~~~~~~
+!!! error TS2339: Property 'toFixed' does not exist on type 'string | number'.
+!!! error TS2339:   Property 'toFixed' does not exist on type 'string'.
+    mod1.bothAfter.toFixed() // error, 'toFixed' not on 'string | number'
+                   ~~~~~~~
+!!! error TS2339: Property 'toFixed' does not exist on type 'string | number'.
+!!! error TS2339:   Property 'toFixed' does not exist on type 'string'.
+    mod1.justProperty.length
+
+==== tests/cases/conformance/salsa/requires.d.ts (0 errors) ====
+    declare var module: { exports: any };
+    declare function require(name: string): any;
+==== tests/cases/conformance/salsa/mod1.js (0 errors) ====
+    /// <reference path='./requires.d.ts' />
+    module.exports.bothBefore = 'string'
+    module.exports = {
+        justExport: 1,
+        bothBefore: 2,
+        bothAfter: 3,
+    }
+    module.exports.bothAfter = 'string'
+    module.exports.justProperty = 'string'
+