fix(flow): remove import declaration if import contains only flow types

Author: Mayank1791989

src/__tests__/__snapshots__/es-test.js.snap

@@ -14,6 +14,14 @@ async function test() {
 }"
 `;
 
+exports[`flow should strip whole import if it contains only types 1`] = `
+"'use strict';
+
+function test() {
+  console.log('test');
+}"
+`;
+
 exports[`transform if Async await enabled 1`] = `
 "\\"use strict\\";
 

src/__tests__/es-test.js

@@ -130,6 +130,17 @@ testParseCode('Flow Support can be disabled using flow option', {
   `,
 });
 
+test('flow should strip whole import if it contains only types', () => {
+  const transformed = transform(`
+    import { type A, type B } from 'some-package';
+    function test() {
+      console.log('test');
+    }
+  `);
+
+  expect(transformed.code).toMatchSnapshot();
+});
+
 testParseCode('Support import shorthand', {
   opts,
   throws: false,

src/plugins/transform-flow-strip-types-import-fix.js

@@ -0,0 +1,35 @@
+/* @flow */
+/**
+ * TEMP_FIX (babel 6.x) for import { type A, type B } from 'moduleA';
+ * getting converted to  "import 'moduleA';" but it should be removed
+ *
+ * the current fix is already present in babel plugin v7 so remove
+ * when upgrade to babel 7
+ */
+import syntaxFlow from 'babel-plugin-syntax-flow';
+
+export default function transformFlowStripTypesImportFix() {
+  return {
+    inherits: syntaxFlow,
+
+    visitor: {
+      ImportDeclaration(path: Object) {
+        if (!path.node.specifiers.length) {
+          return;
+        }
+
+        let typeCount = 0;
+
+        path.node.specifiers.forEach(({ importKind }) => {
+          if (importKind === 'type' || importKind === 'typeof') {
+            typeCount += 1;
+          }
+        });
+
+        if (typeCount === path.node.specifiers.length) {
+          path.remove();
+        }
+      },
+    },
+  };
+}

src/presets/es.js

@@ -8,6 +8,8 @@ import transformFlowStripTypes from 'babel-plugin-transform-flow-strip-types';
 import syntaxFlow from 'babel-plugin-syntax-flow';
 import syntaxDynamicImport from 'babel-plugin-syntax-dynamic-import';
 
+import transformFlowStripTypesImportFix from '../plugins/transform-flow-strip-types-import-fix';
+
 export type Opts = {
   flow: boolean,
   asyncAwait: boolean,
@@ -64,7 +66,7 @@ export default (context: any, opts: Opts) => {
       [transformObjectRestSpread, { useBuiltIns: true }],
 
       // flow support
-      ...(opts.flow ? [transformFlowStripTypes, syntaxFlow] : []),
+      ...(opts.flow ? [transformFlowStripTypesImportFix, transformFlowStripTypes, syntaxFlow] : []),
     ].filter(Boolean),
   };
 };