Suggest json files in completion when resolveJsonModule is set and mo…

…dule resolution is node

Fixes microsoft#23899

src/services/pathCompletions.ts

@@ -27,7 +27,7 @@ namespace ts.Completions.PathCompletions {
         const scriptDirectory = getDirectoryPath(scriptPath);
 
         if (isPathRelativeToScript(literalValue) || isRootedDiskPath(literalValue)) {
-            const extensions = getSupportedExtensions(compilerOptions);
+            const extensions = getSupportExtensionsForModuleResolution(compilerOptions);
             if (compilerOptions.rootDirs) {
                 return getCompletionEntriesForDirectoryFragmentWithRootDirs(
                     compilerOptions.rootDirs, literalValue, scriptDirectory, extensions, /*includeExtensions*/ false, compilerOptions, host, scriptPath);
@@ -42,6 +42,13 @@ namespace ts.Completions.PathCompletions {
         }
     }
 
+    function getSupportExtensionsForModuleResolution(compilerOptions: CompilerOptions) {
+        const extensions = getSupportedExtensions(compilerOptions);
+        return compilerOptions.resolveJsonModule && getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.NodeJs ?
+            extensions.concat(Extension.Json) :
+            extensions;
+    }
+
     /**
      * Takes a script path and returns paths for all potential folders that could be merged with its
      * containing folder via the "rootDirs" compiler option
@@ -122,7 +129,7 @@ namespace ts.Completions.PathCompletions {
                         continue;
                     }
 
-                    const foundFileName = includeExtensions ? getBaseFileName(filePath) : removeFileExtension(getBaseFileName(filePath));
+                    const foundFileName = includeExtensions || fileExtensionIs(filePath, Extension.Json) ? getBaseFileName(filePath) : removeFileExtension(getBaseFileName(filePath));
 
                     if (!foundFiles.has(foundFileName)) {
                         foundFiles.set(foundFileName, true);
@@ -162,7 +169,7 @@ namespace ts.Completions.PathCompletions {
 
         const result: NameAndKind[] = [];
 
-        const fileExtensions = getSupportedExtensions(compilerOptions);
+        const fileExtensions = getSupportExtensionsForModuleResolution(compilerOptions);
         if (baseUrl) {
             const projectDir = compilerOptions.project || host.getCurrentDirectory();
             const absolute = isRootedDiskPath(baseUrl) ? baseUrl : combinePaths(projectDir, baseUrl);

tests/cases/fourslash/completionsPathsJsonModule.ts

@@ -0,0 +1,12 @@
+/// <reference path="fourslash.ts" />
+
+// @moduleResolution: node
+// @resolveJsonModule: true
+
+// @Filename: /project/node_modules/test.json
+////not read
+
+// @Filename: /project/index.ts
+////import { } from "/**/";
+
+verify.completionsAt("", ["test.json"], { isNewIdentifierLocation: true });

tests/cases/fourslash/completionsPathsJsonModuleWithAmd.ts

@@ -0,0 +1,12 @@
+/// <reference path="fourslash.ts" />
+
+// @module: amd
+// @resolveJsonModule: true
+
+// @Filename: /project/test.json
+////not read
+
+// @Filename: /project/index.ts
+////import { } from ".//**/";
+
+verify.completionsAt("", [], { isNewIdentifierLocation: true });

tests/cases/fourslash/completionsPathsJsonModuleWithoutResolveJsonModule.ts

@@ -0,0 +1,11 @@
+/// <reference path="fourslash.ts" />
+
+// @moduleResolution: node
+
+// @Filename: /project/test.json
+////not read
+
+// @Filename: /project/index.ts
+////import { } from ".//**/";
+
+verify.completionsAt("", [], { isNewIdentifierLocation: true });

tests/cases/fourslash/completionsPathsRelativeJsonModule.ts

@@ -0,0 +1,12 @@
+/// <reference path="fourslash.ts" />
+
+// @moduleResolution: node
+// @resolveJsonModule: true
+
+// @Filename: /project/test.json
+////not read
+
+// @Filename: /project/index.ts
+////import { } from ".//**/";
+
+verify.completionsAt("", ["test.json"], { isNewIdentifierLocation: true });