fix: 🐛 Allow imported TS in JS SFCs

Previously when importing TypeScript from a plain JavaScript SFC, the
validator value resolver assumed that imported modules would also be
JavaScript (or rather at best flow). This change updates the resolver to
check the extension of the file about to be parsed to use the TypeScript
plugin rather than the flow plugin when the file extension is `.ts` or
`.tsx`

packages/vue-docgen-api/src/utils/getPathFromExportedValue.ts

@@ -11,6 +11,8 @@ import { ParseOptions } from '../parse'
 
 const read = promisify(readFile)
 
+const tsExtensions = /.tsx?$/
+
 export default async function getPathOfExportedValue(
 	pathResolver: (path: string, originalDirNameOverride?: string) => string | null,
 	exportName: string,
@@ -28,10 +30,17 @@ export default async function getPathOfExportedValue(
 		if (!currentFilePath) {
 			return undefined
 		}
+
+		let filePlugins = plugins
+        // Fixes SFCs written in JS having their imported modules being assumed to also be JS
+		if (tsExtensions.test(currentFilePath)) {
+			filePlugins = filePlugins.map(plugin => plugin === 'flow' ? 'typescript' : plugin)
+		}
+
 		const source = await read(currentFilePath, {
 			encoding: 'utf-8'
 		})
-		const ast = cacher(() => parse(source, { parser: buildParser({ plugins }) }), source)
+		const ast = cacher(() => parse(source, { parser: buildParser({ plugins: filePlugins }) }), source)
 
 		visit(ast, {
 			visitExportNamedDeclaration(p) {