feat(magic-redirect): migrate magic-redirect to codemod.com

Author: bjohansebas

package-lock.json

@@ -46,5 +46,8 @@
   },
   "engines": {
     "node": ">=18"
-  }
+  },
+  "workspaces": [
+    "./recipes/*"
+  ]
 }

package.json

@@ -0,0 +1,45 @@
+# Migrate legacy `res.redirect('back')` and `res.location('back')`
+
+Migrates usage of the legacy APIs `res.redirect('back')` and `res.location('back')` to use the recommended approach of accessing the `Referer` header directly from the request object.
+
+## Example
+
+### Migrating `res.redirect('back')`
+
+#### Before
+
+```js
+app.get('/some-route', (req, res) => {
+  // Some logic here
+    res.redirect('back');
+});
+```
+
+#### After
+
+```js
+app.get('/some-route', (req, res) => {
+  // Some logic here
+    res.redirect(req.get('Referer') || '/');
+});
+```
+
+### Migrating `res.location('back')`
+
+#### Before
+
+```js
+app.get('/some-route', (req, res) => {
+  // Some logic here
+    res.location('back');
+});
+```
+
+#### After
+
+```js
+app.get('/some-route', (req, res) => {
+  // Some logic here
+    res.location(req.get('Referer') || '/');
+});
+```

recipes/magic-redirect/README.md

@@ -0,0 +1,24 @@
+schema_version: "1.0"
+name: "@expressjs/magic-redirect"
+version: "1.0.0"
+description: Migrates usage of the legacy APIs `res.redirect('back')` and `res.location('back')` to the current recommended approaches
+author: bjohansebas (Sebastian Beltran)
+license: MIT
+workflow: workflow.yaml
+category: migration
+
+targets:
+  languages:
+    - javascript
+    - typescript
+
+keywords:
+  - transformation
+  - migration
+  - express
+  - redirect
+  - location
+
+registry:
+  access: public
+  visibility: public

recipes/magic-redirect/codemod.yaml

@@ -0,0 +1,22 @@
+{
+  "name": "@expressjs/magic-redirect",
+  "private": true,
+  "version": "1.0.0",
+  "description": "Migrates usage of the legacy APIs `res.redirect('back')` and `res.location('back')`.",
+  "type": "module",
+  "scripts": {
+    "test": "npx codemod jssg test -l typescript ./src/workflow.ts ./"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/expressjs/codemod.git",
+    "directory": "recipes/magic-redirect",
+    "bugs": "https://github.com/expressjs/codemod/issues"
+  },
+  "author": "bjohansebas (Sebastian Beltran)",
+  "license": "MIT",
+  "homepage": "https://github.com/expressjs/codemod/blob/main/recipes/magic-redirect/README.md",
+  "devDependencies": {
+    "@codemod.com/jssg-types": "^1.3.1"
+  }
+}

recipes/magic-redirect/package.json

@@ -0,0 +1,69 @@
+import type { SgRoot } from "@codemod.com/jssg-types/src/main";
+import type Js from '@codemod.com/jssg-types/src/langs/javascript';
+
+async function transform(root: SgRoot<Js>): Promise<string> {
+  const rootNode = root.root();
+  
+  // Helper function to find the request parameter name
+  function findRequestParamName(node: any): string {
+    // Start from the call expression and traverse up to find function parameters
+    let current = node;
+    while (current) {
+      const parent = current.parent();
+      if (!parent) break;
+      // Check if we're in a function declaration or arrow function
+      if (parent.kind() === 'function_declaration' || parent.kind() === 'arrow_function') {
+        const params = parent.field('parameters');
+
+        if (params && params.children().length > 0) {
+          const firstParam = params.children()[1];
+          if (firstParam.kind() === 'required_parameter') {
+            const pattern = firstParam.field('pattern');
+            if (pattern && pattern.kind() === 'identifier') {
+              return pattern.text();
+            }
+          }
+        }
+      }
+
+      current = parent;
+    }
+    return 'req'; // default fallback
+  }
+
+  // Find all redirect and location
+  const nodes = rootNode.findAll({
+    rule: {
+      any: [
+        {
+          pattern: "$OBJ.redirect($ARG)",
+        },
+        {
+          pattern: "$OBJ.location($ARG)",
+        }]
+      }
+  });
+
+  const edits = nodes.reduce((acc: any[], node: any) => {
+    const requestParamName = findRequestParamName(node);
+    const obj = node.getMatch("OBJ");
+    const arg = node.getMatch("ARG");
+
+    // Only transform when the argument is the literal 'back' (single or double quotes)
+    const argText = arg && typeof arg.text === 'function' ? arg.text() : null;
+    if (argText !== "'back'" && argText !== '"back"' && argText !== "‘back’" && argText !== "“back”") {
+      return acc; // skip this node, no edit
+    }
+
+    // Case: obj.redirect('back') or obj.location('back')
+    const objText = obj?.text();
+    const methodName = node.text().includes('.redirect(') ? 'redirect' : 'location';
+    acc.push(node.replace(`${objText}.${methodName}(${requestParamName}.get("Referrer") || "/")`));
+    return acc;
+  }, [] as any[]);
+
+  const newSource = rootNode.commitEdits(edits);
+  return newSource;
+}
+
+export default transform;

recipes/magic-redirect/src/workflow.ts

@@ -0,0 +1,33 @@
+import express from "express";
+import { location } from "somelibrary";
+
+const app = express();
+
+app.get("/", function (req, res) {
+  res.location(req.get("Referrer") || "/");
+});
+app.get("/", (req, res) => {
+  res.location(req.get("Referrer") || "/");
+});
+app.get("/", (req, res) => {
+  res.location("testing");
+});
+app.get("/", (req, res) => {
+  res.location();
+});
+app.get("/articles", function (request, response) {
+  response.location(request.get("Referrer") || "/");
+});
+app.get("/articles", function (request, response) {
+  response.location("testing");
+});
+app.get("/articles", (request, response) => {
+  response.location(request.get("Referrer") || "/");
+});
+app.get("/articles", function (_req, _res) {
+  location("back");
+});
+
+export function handleLocation(req, res) {
+  res.location(req.get("Referrer") || "/");
+}

recipes/magic-redirect/tests/expected/location.ts

@@ -0,0 +1,20 @@
+import express from "express";
+import { redirect } from "somelibrary";
+
+const app = express();
+
+app.get("/", function (req, res) {
+  res.redirect(req.get("Referrer") || "/");
+});
+app.get("/", (req, res) => {
+  res.redirect(req.get("Referrer") || "/");
+});
+app.get("/articles", function (request, response) {
+  response.redirect(request.get("Referrer") || "/");
+});
+app.get("/articles", (request, response) => {
+  response.redirect(request.get("Referrer") || "/");
+});
+app.get("/articles", function (_req, _res) {
+  redirect("back");
+});

recipes/magic-redirect/tests/expected/redirect.ts

@@ -0,0 +1,33 @@
+import express from "express";
+import { location } from "somelibrary";
+
+const app = express();
+
+app.get("/", function (req, res) {
+  res.location('back');
+});
+app.get("/", (req, res) => {
+  res.location("back");
+});
+app.get("/", (req, res) => {
+  res.location("testing");
+});
+app.get("/", (req, res) => {
+  res.location();
+});
+app.get("/articles", function (request, response) {
+  response.location("back");
+});
+app.get("/articles", function (request, response) {
+  response.location("testing");
+});
+app.get("/articles", (request, response) => {
+  response.location("back");
+});
+app.get("/articles", function (_req, _res) {
+  location("back");
+});
+
+export function handleLocation(req, res) {
+  res.location('back');
+}

recipes/magic-redirect/tests/input/location.ts

@@ -0,0 +1,20 @@
+import express from "express";
+import { redirect } from "somelibrary";
+
+const app = express();
+
+app.get("/", function (req, res) {
+  res.redirect("back");
+});
+app.get("/", (req, res) => {
+  res.redirect("back");
+});
+app.get("/articles", function (request, response) {
+  response.redirect("back");
+});
+app.get("/articles", (request, response) => {
+  response.redirect("back");
+});
+app.get("/articles", function (_req, _res) {
+  redirect("back");
+});