@@ -17,6 +17,7 @@ const {
1717 mimeToFormat,
1818} = require ( 'internal/modules/esm/formats' ) ;
1919
20+ const detectModule = getOptionValue ( '--experimental-detect-module' ) ;
2021const experimentalNetworkImports =
2122getOptionValue ( '--experimental-network-imports' ) ;
2223const { containsModuleSyntax} = internalBinding ( 'contextify' ) ;
@@ -33,6 +34,17 @@ const protocolHandlers = {
3334'node:' ( ) { return 'builtin' ; } ,
3435} ;
3536
37+ /**
38+ * Determine whether the given ambiguous source contains CommonJS or ES module syntax.
39+ *@param {string | Buffer | undefined } source
40+ *@param {URL } url
41+ */
42+ function detectModuleFormat ( source , url ) {
43+ if ( ! source ) { return detectModule ?null :'commonjs' ; }
44+ if ( ! detectModule ) { return 'commonjs' ; }
45+ return containsModuleSyntax ( `${ source } , fileURLToPath ( url ) , url ) ?'module' :'commonjs' ;
46+ }
47+
3648/**
3749 *@param {URL } parsed
3850 *@returns {string | null }
@@ -112,26 +124,23 @@ function getFileProtocolModuleFormat(url, context = { __proto__: null }, ignoreE
112124default :{ // The user did not pass `--experimental-default-type`.
113125// `source` is undefined when this is called from `defaultResolve`;
114126// but this gets called again from `defaultLoad`/`defaultLoadSync`.
115- if ( getOptionValue ( '--experimental-detect-module' ) ) {
116- const format = source ?
117- ( containsModuleSyntax ( `${ source } , fileURLToPath ( url ) , url ) ?'module' :'commonjs' ) :
118- null ;
119- if ( format === 'module' ) {
120- // This module has a .js extension, a package.json with no `type` field, and ESM syntax.
121- // Warn about the missing `type` field so that the user can avoid the performance penalty of detection.
122- typelessPackageJsonFilesWarnedAbout ??= new SafeSet ( ) ;
123- if ( ! typelessPackageJsonFilesWarnedAbout . has ( pjsonPath ) ) {
124- const warning = `${ url } +
125- ` to avoid the performance penalty of syntax detection, add "type": "module" to${ pjsonPath } ;
126- process . emitWarning ( warning , {
127- code :'MODULE_TYPELESS_PACKAGE_JSON' ,
128- } ) ;
129- typelessPackageJsonFilesWarnedAbout . add ( pjsonPath ) ;
130- }
127+ // For ambiguous files (no type field, .js extension) we return
128+ // undefined from `resolve` and re-run the check in `load`.
129+ const format = detectModuleFormat ( source , url ) ;
130+ if ( format === 'module' ) {
131+ // This module has a .js extension, a package.json with no `type` field, and ESM syntax.
132+ // Warn about the missing `type` field so that the user can avoid the performance penalty of detection.
133+ typelessPackageJsonFilesWarnedAbout ??= new SafeSet ( ) ;
134+ if ( ! typelessPackageJsonFilesWarnedAbout . has ( pjsonPath ) ) {
135+ const warning = `${ url } +
136+ ` to avoid the performance penalty of syntax detection, add "type": "module" to${ pjsonPath } ;
137+ process . emitWarning ( warning , {
138+ code :'MODULE_TYPELESS_PACKAGE_JSON' ,
139+ } ) ;
140+ typelessPackageJsonFilesWarnedAbout . add ( pjsonPath ) ;
131141}
132- return format ;
133142}
134- return 'commonjs' ;
143+ return format ;
135144}
136145}
137146}
@@ -154,15 +163,14 @@ function getFileProtocolModuleFormat(url, context = { __proto__: null }, ignoreE
154163return 'commonjs' ;
155164}
156165default :{ // The user did not pass `--experimental-default-type`.
157- if ( getOptionValue ( '--experimental-detect-module' ) ) {
158- if ( ! source ) { return null ; }
159- const format = getFormatOfExtensionlessFile ( url ) ;
160- if ( format === 'module' ) {
161- return containsModuleSyntax ( `${ source } , fileURLToPath ( url ) , url ) ?'module' :'commonjs' ;
162- }
166+ if ( ! source ) {
167+ return null ;
168+ }
169+ const format = getFormatOfExtensionlessFile ( url ) ;
170+ if ( format === 'wasm' ) {
163171return format ;
164172}
165- return 'commonjs' ;
173+ return detectModuleFormat ( source , url ) ;
166174}
167175}
168176}