Merge pull request #171 from debrisapron/dynamic-import

Amend shapeshifter to allow use of dynamic import

packages/eval/shapeshifter.mjs

@@ -34,7 +34,7 @@ export const wrappedAsync = true;
 
 export default (_code) => {
   const { code, addReturn } = wrapAsync(_code);
-  const ast = parseScriptWithLocation(code);
+  const ast = parseScriptWithLocation(disguiseImports(code));
   const artificialNodes = [];
   const parents = [];
   const shifted = replace(ast.tree, {
@@ -128,10 +128,22 @@ export default (_code) => {
   if (wrappedAsync) {
     addReturn(shifted);
   }
-  const generated = codegen(shifted);
+  const generated = undisguiseImports(codegen(shifted));
   return generated;
 };
 
+// renames all import statements to "_mport" as Shift doesn't support dynamic import.
+// there shouldn't be any side-effects from this as this change does not affect
+// the syntax & will be undone by the equivalent replace in "undisguiseImports".
+function disguiseImports(code) {
+  return code.replaceAll('import', '_mport'); // Must be the same length!
+}
+
+// Rename the renamed import statements back to "import"
+function undisguiseImports(code) {
+  return code.replaceAll('_mport', 'import');
+}
+
 function wrapAsync(code) {
   // wrap code in async to make await work on top level => this will create 1 line offset to locations
   // this is why line offset is -1 in getLocationObject calls below

packages/eval/test/shapeshifter.test.mjs

@@ -11,4 +11,10 @@ describe('shapeshifter', () => {
   it('Should shift simple double quote string', () => {
     assert.equal(shapeshifter('"c3"'), '(async()=>{return mini("c3").withMiniLocation([1,0,15],[1,4,19])})()');
   });
+  it('Should handle dynamic imports', () => {
+    assert.equal(
+      shapeshifter('const { default: foo } = await import(\'https://bar.com/foo.js\');"c3"'),
+      '(async()=>{const{default:foo}=await import("https://bar.com/foo.js");return mini("c3").withMiniLocation([1,64,79],[1,68,83])})()',
+    );
+  });
 });