feat: allow .ts .tsx import and resolution

Author: Jack-Works

src/compiler/moduleNameResolver.ts

@@ -1077,13 +1077,21 @@ namespace ts {
 
         // If that didn't work, try stripping a ".js" or ".jsx" extension and replacing it with a TypeScript one;
         // e.g. "./foo.js" can be matched by "./foo.ts" or "./foo.d.ts"
-        if (hasJSFileExtension(candidate)) {
+        if (hasJSFileExtension(candidate, state.compilerOptions)) {
             const extensionless = removeFileExtension(candidate);
             if (state.traceEnabled) {
                 const extension = candidate.substring(extensionless.length);
                 trace(state.host, Diagnostics.File_name_0_has_a_1_extension_stripping_it, candidate, extension);
             }
             return tryAddingExtensions(extensionless, extensions, onlyRecordFailures, state);
+        } else if (hasTSFileExtension(candidate)) {
+            // If import './x.ts' or './x.tsx', resolve it
+            // if import from '.d.ts', bypass it
+            const ext = tryExtractTSExtension(candidate)!;
+            if (ext !== '.d.ts') {
+                const extensionLess = tryRemoveExtension(candidate, ext)!;
+                return tryAddingExtensions(extensionLess, extensions, onlyRecordFailures, state);
+            }
         }
     }
 

tests/baselines/reference/decoratorOnClassConstructor2.symbols

@@ -25,5 +25,6 @@ export class C  extends base{
 >prop : Symbol(prop, Decl(2.ts, 3, 16))
 
         super();
+>super : Symbol(base, Decl(0.ts, 0, 0))
     }
 }

tests/baselines/reference/decoratorOnClassConstructor2.types

@@ -10,21 +10,21 @@ export function foo(target: Object, propertyKey: string | symbol, parameterIndex
 
 === tests/cases/conformance/decorators/class/constructor/2.ts ===
 import {base} from "./0.ts"
->base : any
+>base : typeof base
 
 import {foo} from "./0.ts"
->foo : any
+>foo : (target: Object, propertyKey: string | symbol, parameterIndex: number) => void
 
 export class C  extends base{
 >C : C
->base : error
+>base : base
 
     constructor(@foo prop: any) {
->foo : error
+>foo : (target: Object, propertyKey: string | symbol, parameterIndex: number) => void
 >prop : any
 
         super();
 >super() : void
->super : error
+>super : typeof base
     }
 }

tests/baselines/reference/emitExtensionDisabled.types

@@ -3,10 +3,10 @@ export default 1
 No type information for this code.
 No type information for this code.=== tests/cases/compiler/1.ts ===
 import a from './0.ts'
->a : any
+>a : 1
 
 a + 1
->a + 1 : error
->a : error
+>a + 1 : number
+>a : 1
 >1 : 1
 

tests/baselines/reference/emitExtensionEnabled.types

@@ -3,10 +3,10 @@ export default 1
 No type information for this code.
 No type information for this code.=== tests/cases/compiler/1.ts ===
 import a from './0.ts'
->a : any
+>a : 1
 
 a + 1
->a + 1 : error
->a : error
+>a + 1 : number
+>a : 1
 >1 : 1
 

tests/baselines/reference/emitExtensionInvalidValue.types

@@ -3,10 +3,10 @@ export default 1
 No type information for this code.
 No type information for this code.=== tests/cases/compiler/1.ts ===
 import a from './0.ts'
->a : any
+>a : 1
 
 a + 1
->a + 1 : any
->a : any
+>a + 1 : number
+>a : 1
 >1 : 1
 

tests/baselines/reference/moduleResolutionNoTs.types

@@ -13,10 +13,10 @@ export default x;
 
 === tests/cases/compiler/user.ts ===
 import x from "./x.ts";
->x : any
+>x : 0
 
 import y from "./y.tsx";
->y : any
+>y : 0
 
 import z from "./z.d.ts";
 >z : any

tests/baselines/reference/pathMappingBasedModuleResolution_withExtensionInName.trace.json

@@ -30,6 +30,9 @@
     "File '/foo/zone.tsx.ts' does not exist.",
     "File '/foo/zone.tsx.tsx' does not exist.",
     "File '/foo/zone.tsx.d.ts' does not exist.",
+    "File '/foo/zone.ts' does not exist.",
+    "File '/foo/zone.tsx' does not exist.",
+    "File '/foo/zone.d.ts' does not exist.",
     "File '/foo/zone.tsx/package.json' does not exist.",
     "File '/foo/zone.tsx/index.ts' does not exist.",
     "File '/foo/zone.tsx/index.tsx' does not exist.",

tests/cases/compiler/moduleResolutionNoTs.ts

@@ -1,20 +1,10 @@
 // @jsx: Preserve
-// @filename: x.ts
-export default 0;
-
-// @filename: y.tsx
-export default 0;
-
 // @filename: z.d.ts
 declare const x: number;
 export default x;
 
 // @filename: user.ts
-import x from "./x.ts";
-import y from "./y.tsx";
 import z from "./z.d.ts";
 
 // Making sure the suggested fixes are valid:
-import x2 from "./x";
-import y2 from "./y";
 import z2 from "./z";