fix: ignore dynamic import for has ESM syntax (#164)

guybedford · Nov 12, 2023 · 2eeee5b · 2eeee5b
1 parent b2969ed
commit 2eeee5b
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Showing 6 changed files with 15 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -176,6 +176,15 @@ const [,,, hasModuleSyntax] = parse(`
 hasModuleSyntax === true;
 ```
 
+Dynamic imports are ignored since they can be used in Non-ESM files.
+
+```js
+const [,,, hasModuleSyntax] = parse(`
+  import('./foo.js')
+`);
+hasModuleSyntax === false;
+```
+
 ### Environment Support
 
 Node.js 10+, and [all browsers with Web Assembly support](https://caniuse.com/#feat=wasm).

diff --git a/lib/lexer.asm.js b/lib/lexer.asm.js
diff --git a/lib/lexer.emcc.asm.js b/lib/lexer.emcc.asm.js
diff --git a/lib/lexer.wasm b/lib/lexer.wasm
diff --git a/src/lexer.h b/src/lexer.h
@@ -123,7 +123,8 @@ void addImport (const char16_t* statement_start, const char16_t* start, const ch
   import->dynamic = dynamic;
   import->safe = dynamic == STANDARD_IMPORT;
   import->next = NULL;
-  hasModuleSyntax = true;
+  if (dynamic == IMPORT_META || dynamic == STANDARD_IMPORT)
+    hasModuleSyntax = true;
 }
 
 void addExport (const char16_t* start, const char16_t* end, const char16_t* local_start, const char16_t* local_end) {

diff --git a/test/_unit.cjs b/test/_unit.cjs
@@ -1399,7 +1399,8 @@ function x() {
   })
   test('hasModuleSyntax import3', () => {
     const [,,, hasModuleSyntax] = parse('import("./foo")')
-    assert.strictEqual(hasModuleSyntax, true)
+    // dynamic imports can be used in non-ESM files as well
+    assert.strictEqual(hasModuleSyntax, false)
   })
   test('hasModuleSyntax import4', () => {
     const [,,, hasModuleSyntax] = parse('import.meta.url')