feat(redirect-arg-order): add migration codemod for res.redirect argument order (#99)

* feat(redirect-arg-order): add migration codemod for res.redirect argument order

* refactor(workflow): simplify early return checks for nodes and edits

* fix(codemod.yaml): update repository URL for redirect-arg-order migration

* fix(docs): clarify deprecation notice for res.redirect argument order migration

Author: bjohansebas

codemods/redirect-arg-order/README.md

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+# Migrate legacy `res.redirect(url, status)`
+
+Migrates usage of the legacy APIs `res.redirect(url, status)` to the new signature
+`res.redirect(status, url)`. This usage was deprecated in Express 4, in Express 5 you must use the new signature `res.redirect(status, url)`.
+
+## Example
+
+### Migrating `res.redirect(url, status)`
+
+The migration involves replacing instances of `res.redirect(url, status)` with `res.redirect(status, url)`.
+
+```diff
+app.get('/some-route', (req, res) => {
+  // Some logic here
+- res.redirect(url, status);
++ res.redirect(status, url);
+});
+```
+
+## References
+
+- [Migration of res.redirect(url, status)](https://expressjs.com/en/guide/migrating-5.html#res.redirect)

codemods/redirect-arg-order/codemod.yaml

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+schema_version: "1.0"
+name: "@expressjs/redirect-arg-order"
+version: "1.0.0"
+description: Migrates usage of the legacy APIs `res.redirect(url, status)` to use the recommended argument order `res.redirect(status, url)`.
+author: bjohansebas (Sebastian Beltran)
+license: MIT
+workflow: workflow.yaml
+repository: "https://github.com/expressjs/codemod/tree/HEAD/codemods/redirect-arg-order"
+category: migration
+
+targets:
+  languages:
+    - javascript
+    - typescript
+
+keywords:
+  - transformation
+  - migration
+  - express
+  - redirect
+  - location
+
+registry:
+  access: public
+  visibility: public

codemods/redirect-arg-order/package.json

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+{
+  "name": "@expressjs/redirect-arg-order",
+  "private": true,
+  "version": "1.0.0",
+  "description": "Migrates usage of the legacy APIs `res.redirect(url, status)` to use the recommended argument order `res.redirect(status, url)`.",
+  "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": "codemods/redirect-arg-order",
+    "bugs": "https://github.com/expressjs/codemod/issues"
+  },
+  "author": "bjohansebas (Sebastian Beltran)",
+  "license": "MIT",
+  "homepage": "https://github.com/expressjs/codemod/blob/main/codemods/redirect-arg-order/README.md",
+  "devDependencies": {
+    "@codemod.com/jssg-types": "^1.3.1"
+  }
+}

codemods/redirect-arg-order/src/workflow.ts

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+import type Js from '@codemod.com/jssg-types/src/langs/javascript'
+import type { Edit, SgRoot } from '@codemod.com/jssg-types/src/main'
+
+async function transform(root: SgRoot<Js>): Promise<string | null> {
+  const rootNode = root.root()
+
+  const nodes = rootNode.findAll({
+    rule: {
+      pattern: '$OBJ.$METHOD($$$ARG)',
+    },
+    constraints: {
+      METHOD: { regex: '^(redirect)$' },
+    },
+  })
+
+  if (!nodes.length) return null
+
+  const edits: Edit[] = []
+
+  for (const call of nodes) {
+    const obj = call.getMatch('OBJ')
+    const args = call.getMultipleMatches('ARG')
+    if (!obj || args.length < 3) continue
+
+    const objDef = obj.definition({ resolveExternal: false })
+    if (!objDef) continue
+
+    // $$$ARG yields argument nodes interleaved with separators, so arg nodes are at 0,2,4...
+    const first = args[0]
+    const second = args[2]
+    if (!first || !second) continue
+
+    // Only transform legacy form redirect(url, status) where second is number
+    if (second.is('number') && !first.is('number')) {
+      edits.push(call.replace(`${obj.text()}.redirect(${second.text()}, ${first.text()})`))
+    }
+  }
+
+  if (!edits.length) return null
+
+  return rootNode.commitEdits(edits)
+}
+
+export default transform

codemods/redirect-arg-order/tests/expected/redirect.ts

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+import express from "express";
+import { redirect } from "somelibrary";
+
+const app = express();
+
+app.get("/", function (...arg) {
+  const [, res] = arg
+  res.redirect();
+});
+
+app.get("/", function (...arg) {
+  const [, res] = arg
+  res.redirect(301, "/other-page");
+});
+
+app.get("/", function (req, res) {
+  res.redirect();
+});
+
+app.get("/", function (req, res) {
+  res.redirect(301, "/other-page");
+});
+
+app.get("/", function (req, response) {
+  response.redirect(301, "/other-page");
+});
+
+app.get("/", function (req, res) {
+  res.redirect(301, "/other-page");
+});
+
+app.get("/", function (req, res) {
+  res.redirect("/other-page");
+});
+
+app.get("/", function (req, res) {
+  redirect(301, "/other-page");
+});

codemods/redirect-arg-order/tests/input/redirect.ts

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+import express from "express";
+import { redirect } from "somelibrary";
+
+const app = express();
+
+app.get("/", function (...arg) {
+  const [, res] = arg
+  res.redirect();
+});
+
+app.get("/", function (...arg) {
+  const [, res] = arg
+  res.redirect("/other-page", 301);
+});
+
+app.get("/", function (req, res) {
+  res.redirect();
+});
+
+app.get("/", function (req, res) {
+  res.redirect("/other-page", 301);
+});
+
+app.get("/", function (req, response) {
+  response.redirect("/other-page", 301);
+});
+
+app.get("/", function (req, res) {
+  res.redirect(301, "/other-page");
+});
+
+app.get("/", function (req, res) {
+  res.redirect("/other-page");
+});
+
+app.get("/", function (req, res) {
+  redirect(301, "/other-page");
+});

codemods/redirect-arg-order/workflow.yaml

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+# yaml-language-server: $schema=https://raw.githubusercontent.com/codemod-com/codemod/refs/heads/main/schemas/workflow.json
+
+version: "1"
+
+nodes:
+  - id: apply-transforms
+    name: Apply AST Transformations
+    type: automatic
+    runtime:
+      type: direct
+    steps:
+      - name: Migrates usage of the legacy APIs `res.redirect(url, status)` to use the recommended argument order `res.redirect(status, url)`.
+        js-ast-grep:
+          js_file: src/workflow.ts
+          base_path: .
+          semantic_analysis: file
+          include:
+            - "**/*.cjs"
+            - "**/*.js"
+            - "**/*.jsx"
+            - "**/*.mjs"
+            - "**/*.cts"
+            - "**/*.mts"
+            - "**/*.ts"
+            - "**/*.tsx"
+          exclude:
+            - "**/node_modules/**"
+          language: typescript