Add support for babel-plugin-transform-typescript

packages/babel-plugin-transform-typescript/src/index.ts

@@ -229,9 +229,23 @@ export default declare((api, opts) => {
                 continue;
               }
 
+              const importsToRemove: NodePath<t.Node>[] = [];
+              const specifiersLength = stmt.node.specifiers.length;
+              const isAllSpecifiersElided = () =>
+                specifiersLength > 0 &&
+                specifiersLength === importsToRemove.length;
+
               // If onlyRemoveTypeImports is `true`, only remove type-only imports
               // and exports introduced in TypeScript 3.8.
               if (onlyRemoveTypeImports) {
+                for (const specifier of stmt.node.specifiers) {
+                  if (specifier.importKind === "type") {
+                    const binding = stmt.scope.getBinding(specifier.local.name);
+                    if (binding) {
+                      importsToRemove.push(binding.path);
+                    }
+                  }
+                }
                 NEEDS_EXPLICIT_ESM.set(path.node, false);
               } else {
                 // Note: this will allow both `import { } from "m"` and `import "m";`.
@@ -241,9 +255,6 @@ export default declare((api, opts) => {
                   continue;
                 }
 
-                let allElided = true;
-                const importsToRemove: NodePath<t.Node>[] = [];
-
                 for (const specifier of stmt.node.specifiers) {
                   const binding = stmt.scope.getBinding(specifier.local.name);
 
@@ -264,17 +275,16 @@ export default declare((api, opts) => {
                   ) {
                     importsToRemove.push(binding.path);
                   } else {
-                    allElided = false;
                     NEEDS_EXPLICIT_ESM.set(path.node, false);
                   }
                 }
+              }
 
-                if (allElided) {
-                  stmt.remove();
-                } else {
-                  for (const importPath of importsToRemove) {
-                    importPath.remove();
-                  }
+              if (isAllSpecifiersElided()) {
+                stmt.remove();
+              } else {
+                for (const importPath of importsToRemove) {
+                  importPath.remove();
                 }
               }
 
@@ -325,6 +335,17 @@ export default declare((api, opts) => {
           return;
         }
 
+        // remove export declaration that is filled with type-only specifiers
+        //   export { type A1, type A2 } from "a";
+        if (
+          path.node.source &&
+          path.node.specifiers.length > 0 &&
+          path.node.specifiers.every(({ exportKind }) => exportKind === "type")
+        ) {
+          path.remove();
+          return;
+        }
+
         // remove export declaration if it's exporting only types
         // This logic is needed when exportKind is "value", because
         // currently the "type" keyword is optional.
@@ -348,7 +369,10 @@ export default declare((api, opts) => {
 
       ExportSpecifier(path) {
         // remove type exports
-        if (!path.parent.source && isGlobalType(path, path.node.local.name)) {
+        if (
+          (!path.parent.source && isGlobalType(path, path.node.local.name)) ||
+          path.node.exportKind === "type"
+        ) {
           path.remove();
         }
       },

packages/babel-plugin-transform-typescript/test/fixtures/exports/type-only-export-specifier-1/input.ts

@@ -0,0 +1,2 @@
+class Foo {}
+export { type Foo };

packages/babel-plugin-transform-typescript/test/fixtures/exports/type-only-export-specifier-1/output.mjs

@@ -0,0 +1,3 @@
+class Foo {}
+
+export {};

packages/babel-plugin-transform-typescript/test/fixtures/exports/type-only-export-specifier-2/input.ts

@@ -0,0 +1 @@
+export { type A1, type A2 } from "a"

packages/babel-plugin-transform-typescript/test/fixtures/exports/type-only-export-specifier-2/output.mjs

@@ -0,0 +1 @@
+export {};

packages/babel-plugin-transform-typescript/test/fixtures/exports/type-only-export-specifier-3/input.ts

@@ -0,0 +1 @@
+export { type A1, type A2, A3 } from "a"

packages/babel-plugin-transform-typescript/test/fixtures/exports/type-only-export-specifier-3/output.mjs

@@ -0,0 +1 @@
+export { A3 } from "a";

packages/babel-plugin-transform-typescript/test/fixtures/imports/only-remove-type-imports/input.ts

@@ -10,4 +10,6 @@ import "g";
 import type H from "h";
 import type { I, I2 } from "i";
 import type * as J from "j";
+import { type K1, type K2 } from "k";
+import { type L1, L2, type L3 } from "l";
 ;

packages/babel-plugin-transform-typescript/test/fixtures/imports/only-remove-type-imports/output.mjs

@@ -5,4 +5,5 @@ import d, { d2 } from "d";
 import e, { e3 as e4 } from "e";
 import "f";
 import "g";
+import { L2 } from "l";
 ;

packages/babel-plugin-transform-typescript/test/fixtures/imports/type-only-import-specifier-1/input.ts

@@ -0,0 +1,2 @@
+import { Foo1, type Foo2  } from "Foo";
+Foo1;

packages/babel-plugin-transform-typescript/test/fixtures/imports/type-only-import-specifier-1/output.mjs

@@ -0,0 +1,2 @@
+import { Foo1 } from "Foo";
+Foo1;

packages/babel-plugin-transform-typescript/test/fixtures/imports/type-only-import-specifier-2/input.ts

@@ -0,0 +1 @@
+import { type Foo1, type Foo2 } from "Foo";

packages/babel-plugin-transform-typescript/test/fixtures/imports/type-only-import-specifier-2/output.mjs

@@ -0,0 +1 @@
+export {};