refactor: simplify loader detection

README.md

@@ -133,9 +133,11 @@ const mod = await import('importx')
 
 ## Runtime-Loader Compatibility Table
 
+Importing a TypeScript module with `importx`:
+
 <!-- TABLE_START -->
 
-> Generated with version v0.0.1 at 2024-05-11T03:58:02.482Z
+> Generated with version v0.0.2 at 2024-05-11T04:17:16.249Z
 
 | | native | tsx | jiti | bundle-require |
 | ------- | --- | --- | --- | --- |

src/index.ts

@@ -105,12 +105,22 @@ export async function isNativeTsImportSupported(): Promise<boolean> {
  return _isNativeTsImportSupported
 }
 
-async function _detectLoaderImpl(): Promise<SupportedLoader> {
- if (await isNativeTsImportSupported())
+const nodeVersionNumbers = globalThis?.process?.versions?.node?.split('.').map(Number)
+
+/**
+ * Detect the 'auto' loader to use for importing the file.
+ */
+async function detectLoader(cache: boolean | null, isTsFile: boolean): Promise<SupportedLoader> {
+ if (cache === false)
+ return 'tsx'
+
+ if (!isTsFile || await isNativeTsImportSupported())
  return 'native'
 
- const nodeVersion = globalThis?.process?.versions?.node?.split('.').map(Number)
- if (!nodeVersion)
+ if (cache === true)
+ return 'jiti'
+
+ if (!nodeVersionNumbers)
  return 'tsx'
 
  /**
@@ -120,30 +130,19 @@ async function _detectLoaderImpl(): Promise<SupportedLoader> {
  * @see https://nodejs.org/api/module.html#moduleregisterspecifier-parenturl-options
  */
  if (
- nodeVersion[0] < 18
- || (nodeVersion[0] === 18 && nodeVersion[1] < 19)
- || (nodeVersion[0] === 20 && nodeVersion[1] < 8)
+ nodeVersionNumbers[0] < 18
+ || (nodeVersionNumbers[0] === 18 && nodeVersionNumbers[1] < 19)
+ || (nodeVersionNumbers[0] === 20 && nodeVersionNumbers[1] < 8)
  )
  return 'jiti'
 
  return 'tsx'
 }
 
-let _loader: Promise<SupportedLoader>
-
-/**
- * Detect the 'auto' loader to use for importing the file.
- */
-export async function detectLoader() {
- if (!_loader)
- _loader = _detectLoaderImpl()
- return _loader
-}
-
 const reIsTypeScriptFile = /\.[mc]?tsx?$/
 
 export function isTypeScriptFile(path: string) {
- return path.match(reIsTypeScriptFile)
+ return reIsTypeScriptFile.test(path)
 }
 
 /**
@@ -173,18 +172,8 @@ export async function importTs<T = any>(path: string, options: string | URL | Im
  } = options
 
  let loader = options.loader || 'auto'
- if (loader === 'auto') {
- if (cache === false) {
- loader = 'tsx'
- }
- else {
- loader = isTypeScriptFile(path)
- ? await detectLoader()
- : 'native'
- if (cache === true && (loader === 'tsx' || loader === 'bundle-require'))
- loader = 'jiti'
- }
- }
+ if (loader === 'auto')
+ loader = await detectLoader(cache, isTypeScriptFile(path))
 
  debug(`[${loader}]`, 'Importing', path, 'from', parentURL)
 

test/run-table.mjs

@@ -46,7 +46,7 @@ for (const loader of loaders) {
  if (stderr)
  object.errors = stderr
 
- console.log(object, { stdout })
+ console.log(object)
 
  records.push(object)
  }