fix(gatsby): only remove unused code when apis got removed

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/default/input.mjs

@@ -0,0 +1,20 @@
+import { fetch, Response } from 'node-fetch';
+
+const usedReference = 'my cool ref';
+const unusedReference = 'I hope to be removed';
+
+export default function () {
+  const x = new Response({})
+  anotherSelfReferencedOne();
+
+  return usedReference
+}
+
+// such a structure is being generated by regenerator-runtime
+function renderPage() {
+  renderPage = () => { };
+}
+
+function anotherSelfReferencedOne() {
+  anotherSelfReferencedOne = () => { };
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/default/output.mjs

@@ -0,0 +1,16 @@
+import { fetch, Response } from 'node-fetch';
+const usedReference = 'my cool ref';
+const unusedReference = 'I hope to be removed';
+export default function () {
+  const x = new Response({});
+  anotherSelfReferencedOne();
+  return usedReference;
+} // such a structure is being generated by regenerator-runtime
+
+function renderPage() {
+  renderPage = () => {};
+}
+
+function anotherSelfReferencedOne() {
+  anotherSelfReferencedOne = () => {};
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/exports/input.mjs

@@ -1,7 +1,4 @@
-import * as fs from "fs"
-
 const { fetch, Response } = require('node-fetch');
-const unusedReference = fs.readFileSync('./myfile.json');
 const usedReference = 'used reference';
 
 module.exports = function () {

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/jsx/input.mjs

@@ -0,0 +1,7 @@
+/** @jsx jsx */
+import { jsx } from 'react'
+
+export default function MyComponent() {
+  return <div>Hello World</div>
+}
+

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/jsx/options.json

@@ -0,0 +1,16 @@
+{
+  "presets": [
+    "@babel/preset-react"
+  ],
+  "plugins": [
+    [
+      "../../../../babel-plugin-remove-api",
+      {
+        "apis": [
+          "getServerData",
+          "config"
+        ]
+      }
+    ]
+  ]
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/jsx/output.mjs

@@ -0,0 +1,5 @@
+/** @jsx jsx */
+import { jsx } from 'react';
+export default function MyComponent() {
+  return jsx("div", null, "Hello World");
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/options.json

@@ -10,4 +10,4 @@
       }
     ]
   ]
-}
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/react/input.mjs

@@ -0,0 +1,5 @@
+import React from 'react';
+
+export default function MyComponent() {
+  return <div>Hello World</div>
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/react/options.json

@@ -0,0 +1,16 @@
+{
+  "presets": [
+    "@babel/preset-react"
+  ],
+  "plugins": [
+    [
+      "../../../../babel-plugin-remove-api",
+      {
+        "apis": [
+          "getServerData",
+          "config"
+        ]
+      }
+    ]
+  ]
+}

packages/gatsby/src/utils/babel/__tests__/fixtures/remove-apis/react/output.mjs

@@ -0,0 +1,4 @@
+import React from 'react';
+export default function MyComponent() {
+  return /*#__PURE__*/React.createElement("div", null, "Hello World");
+}

packages/gatsby/src/utils/babel/babel-plugin-remove-api.ts

@@ -20,7 +20,11 @@ export default declare(function removeApiCalls(
     name: `remove-api`,
     visitor: {
       Program: {
-        exit(path): void {
+        exit(path, state): void {
+          if (!state.apiRemoved) {
+            return
+          }
+
           // babel doesn't remove references very well so we loop until nothing gets removed
           let removed = false
 
@@ -90,7 +94,7 @@ export default declare(function removeApiCalls(
       },
 
       // Remove export statements
-      ExportNamedDeclaration(path): void {
+      ExportNamedDeclaration(path, state): void {
         const declaration = path.node.declaration
 
         if (t.isExportNamedDeclaration(path.node)) {
@@ -126,12 +130,13 @@ export default declare(function removeApiCalls(
         }
 
         if (apiToCheck && apisToRemove.includes(apiToCheck)) {
+          state.apiRemoved = true
           path.remove()
         }
       },
 
       // remove exports
-      ExpressionStatement(path): void {
+      ExpressionStatement(path, state): void {
         if (
           !t.isAssignmentExpression(path.node.expression) ||
           !t.isMemberExpression(path.node.expression.left) ||
@@ -143,6 +148,7 @@ export default declare(function removeApiCalls(
         const apiToCheck = (path.node.expression.left.property as t.Identifier)
           .name
         if (apiToCheck && apisToRemove.includes(apiToCheck)) {
+          state.apiRemoved = true
           path.remove()
         }
       },