fix(gatsby): remove unused vars in remove api plugin (gatsbyjs#33476)

e2e-tests/development-runtime/src/pages/ssr/static-path.js

@@ -1,4 +1,6 @@
 import React from "react"
+import path from "path"
+import * as fs from "fs"
 
 export default function StaticPath({ serverData }) {
   return (
@@ -14,8 +16,13 @@ export default function StaticPath({ serverData }) {
 }
 
 export function getServerData(arg) {
+  const pkgJSON = JSON.parse(
+    fs.readFileSync(path.join(__dirname, "../../../package.json"), "utf8")
+  )
+
   return {
     props: {
+      version: pkgJSON.version,
       arg,
     },
   }

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

@@ -0,0 +1,35 @@
+import * as fs from "fs"
+
+const { fetch, Response } = require('node-fetch');
+const unusedReference = fs.readFileSync('./myfile.json');
+const usedReference = 'used reference';
+
+module.exports = function () {
+  const x = new Response({})
+
+  return usedReference
+}
+
+exports.getServerData = async function getServerData() {
+  const data = await fetch('https://example.com');
+  const file = fs.readFileSync('./unknown.tmp.json', 'utf8')
+
+  return {
+    props: {
+      file,
+    }
+  }
+}
+
+exports.config = function config() {
+  return {
+    pageContext: {
+      env: 'test',
+      unusedReference,
+    },
+  }
+}
+
+exports.anotherFunction = function anotherFunction() {
+  return "test"
+}

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

@@ -0,0 +1,14 @@
+const {
+  Response
+} = require('node-fetch');
+
+const usedReference = 'used reference';
+
+module.exports = function () {
+  const x = new Response({});
+  return usedReference;
+};
+
+exports.anotherFunction = function anotherFunction() {
+  return "test";
+};

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

@@ -0,0 +1,55 @@
+import { fetch, Response } from 'node-fetch';
+import something from 'my-import'
+import * as fs from "fs"
+
+const usedReference = 'my cool ref';
+const unusedReference = 'I hope to be removed';
+const { x, y } = require('some-import');
+
+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 = () => { };
+}
+
+export async function getServerData() {
+  const data = await fetch('https://example.com');
+  const file = fs.readFileSync('./unknown.tmp.json', 'utf8')
+  renderPage();
+  anotherSelfReferencedOne();
+
+  return {
+    props: {
+      x,
+      y,
+      file,
+      data: await data.json(),
+      unusedReference,
+      test: something(),
+    }
+
+  }
+}
+
+export function config() {
+  return {
+    pageContext: {
+      env: 'test',
+      unusedReference,
+    },
+  }
+}
+
+export function anotherFunction() {
+  return "test"
+}

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

@@ -0,0 +1,15 @@
+import { Response } from 'node-fetch';
+const usedReference = 'my cool ref';
+export default function () {
+  const x = new Response({});
+  anotherSelfReferencedOne();
+  return usedReference;
+} // such a structure is being generated by regenerator-runtime
+
+function anotherSelfReferencedOne() {
+  anotherSelfReferencedOne = () => {};
+}
+
+export function anotherFunction() {
+  return "test";
+}

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

@@ -19,6 +19,77 @@ export default declare(function removeApiCalls(
   return {
     name: `remove-api`,
     visitor: {
+      Program: {
+        exit(path): void {
+          // babel doesn't remove references very well so we loop until nothing gets removed
+          let removed = false
+
+          // remove all unreferenced bindings
+          do {
+            removed = false
+            // make sure all references are up to date
+            path.scope.crawl()
+
+            Object.keys(path.scope.bindings).forEach(refName => {
+              const ref = path.scope.bindings[refName]
+
+              if (ref.referenced) {
+                // Functions can reference themselves, so we need to check if there's a
+                // binding outside the function scope or not.
+                if (ref.path.type === `FunctionDeclaration`) {
+                  const isSelfReferenced = ref.referencePaths.every(
+                    refPath => !!refPath.findParent(p => p === ref.path)
+                  )
+
+                  if (isSelfReferenced) {
+                    ref.path.remove()
+                    removed = true
+                  }
+                }
+              } else {
+                // if const {x,y} is used, we remove the property
+                if (
+                  t.isVariableDeclarator(ref.path) &&
+                  t.isObjectPattern(
+                    (ref.path.parent as t.VariableDeclaration).declarations[0]
+                      .id
+                  )
+                ) {
+                  const objectPattern = (
+                    ref.path.parent as t.VariableDeclaration
+                  ).declarations[0].id as t.ObjectPattern
+                  objectPattern.properties = objectPattern.properties.filter(
+                    prop =>
+                      t.isObjectProperty(prop)
+                        ? (prop.value as t.Identifier).name !== refName
+                        : ((prop as t.RestElement).argument as t.Identifier)
+                            .name !== refName
+                  )
+
+                  // if all properties got removed thus the object pattern is empty, we remove the whole declaration
+                  if (!objectPattern.properties.length) {
+                    ref.path.remove()
+                  }
+                } else {
+                  ref.path.remove()
+                }
+
+                // if it's a module and all specifiers are removed, remove the full binding
+                if (
+                  ref.kind === `module` &&
+                  !(ref.path.parent as t.ImportDeclaration).specifiers.length
+                ) {
+                  ref.path.parentPath.remove()
+                }
+
+                removed = true
+              }
+            })
+          } while (removed)
+        },
+      },
+
+      // Remove export statements
       ExportNamedDeclaration(path): void {
         const declaration = path.node.declaration
 
@@ -58,6 +129,23 @@ export default declare(function removeApiCalls(
           path.remove()
         }
       },
+
+      // remove exports
+      ExpressionStatement(path): void {
+        if (
+          !t.isAssignmentExpression(path.node.expression) ||
+          !t.isMemberExpression(path.node.expression.left) ||
+          (path.node.expression.left.object as t.Identifier).name !== `exports`
+        ) {
+          return
+        }
+
+        const apiToCheck = (path.node.expression.left.property as t.Identifier)
+          .name
+        if (apiToCheck && apisToRemove.includes(apiToCheck)) {
+          path.remove()
+        }
+      },
     },
   }
 })