feat(secret): add --write to auth secret

commands/framework.js

@@ -1,5 +1,7 @@
 // @ts-check
 
+import { detectFramework } from "../lib/detect.js"
+
 // TODO: Get this programmatically
 export const frameworks = {
   nextjs: {
@@ -16,8 +18,9 @@ export const frameworks = {
   },
 }
 
-export function action(framework) {
-  if (!framework) {
+export async function action(framework) {
+  framework ??= await detectFramework()
+  if (framework === "unknown") {
     return console.log(`
 Supported frameworks are: ${Object.keys(frameworks).join(", ")}`)
   }

commands/secret.js

@@ -2,6 +2,10 @@
 
 import * as y from "yoctocolors"
 import { write } from "../lib/clipboard/index.js"
+import { detectFramework } from "../lib/detect.js"
+import { readFile, writeFile } from "node:fs/promises"
+import { join } from "node:path"
+import prompt from "prompts"
 
 /** Web compatible method to create a random string of a given length */
 function randomString(size = 32) {
@@ -10,30 +14,97 @@ function randomString(size = 32) {
   return Buffer.from(bytes, "base64").toString("base64")
 }
 
-export function action(options) {
-  let value = randomString()
-  if (options.raw) return console.log(value)
+/** @type {Record<import("../lib/detect.js").SupportedFramework, string>} */
+export const frameworkDotEnvFile = {
+  nextjs: ".env.local",
+  express: ".env",
+  sveltekit: ".env",
+}
 
-  value = `AUTH_SECRET="${value}"`
-  if (!options.copy) return console.log(value)
+export async function action(options) {
+  const key = "AUTH_SECRET"
+  const value = randomString()
+  if (options.raw) return console.log(value)
 
+  const line = `${key}="${value}"`
   const message = {
     introClipboard:
       "Secret generated. It has been copied to your clipboard, paste it to your .env/.env.local file to continue.",
     introCopy:
       "Secret generated. Copy it to your .env/.env.local file (depending on your framework):",
-    value: `\n${value}`,
+    value: `\n${line}`,
+  }
+
+  if (options.copy) {
+    try {
+      write(line)
+      console.log(message.introClipboard)
+    } catch (error) {
+      console.error(y.red(error))
+      console.log(message.introCopy)
+    } finally {
+      console.log(message.value)
+      process.exit(0)
+    }
+  }
+
+  if (options.write) {
+    try {
+      const framework = await detectFramework()
+      if (framework === "unknown") {
+        return console.log(
+          `No framework detected. Currently supported frameworks are: ${y.bold(
+            Object.keys(frameworkDotEnvFile).join(", ")
+          )}`
+        )
+      }
+      const dotEnvFile = frameworkDotEnvFile[framework]
+      await updateEnvFile(
+        dotEnvFile,
+        join(process.cwd(), dotEnvFile),
+        key,
+        value
+      )
+    } catch (error) {
+      console.error(y.red(error))
+    }
   }
+}
 
-  // TODO: Detect framework, check for existing value, and write automatically
+/**
+ * Update a key-value pair to a .env file
+ * @param {string} file
+ * @param {string} envPath
+ * @param {string} key
+ * @param {string} value
+ */
+async function updateEnvFile(file, envPath, key, value) {
+  let content = ""
+  const line = `${key}="${value}" # Added by \`npx auth\`. Read more: https://cli.authjs.dev`
   try {
-    write(value)
-    console.log(message.introClipboard)
+    await readFile(envPath, "utf-8")
+    content = await readFile(envPath, "utf-8")
+    if (!content.includes(`${key}=`)) {
+      console.log(`➕ Added ${key} to ${y.italic(file)}.`)
+      content = `${line}\n${content}`
+    } else {
+      const { overwrite } = await prompt({
+        type: "confirm",
+        name: "overwrite",
+        message: `Overwrite existing ${key}?`,
+        initial: false,
+      })
+      if (!overwrite) return
+      console.log(`✨ Updated ${key} in ${y.italic(file)}.`)
+      content = content.replace(new RegExp(`${key}=(.*)`), `${line}`)
+    }
   } catch (error) {
-    console.error(y.red(error))
-    console.log(message.introCopy)
-  } finally {
-    console.log(message.value)
-    process.exit(0)
+    if (error.code === "ENOENT") {
+      console.log(`📝 Created ${y.italic(file)} with ${key}.`)
+      content = line
+    } else {
+      throw error
+    }
   }
+  if (content) await writeFile(envPath, content)
 }

index.js

@@ -35,7 +35,6 @@ program
 program
   .command("framework")
   .argument("[framework]", "The framework to use.", (value) => {
-    if (!value) return value
     if (Object.keys(framework.frameworks).includes(value)) return value
     throw new InvalidArgumentError(
       `Valid frameworks are: ${framework.frameworks.join(", ")}`
@@ -48,6 +47,7 @@ program
   .command("secret")
   .option("--raw", "Output the string without any formatting.")
   .option("--copy", 'Copy AUTH_SECRET="value"')
+  .option("--write", 'Write AUTH_SECRET="value" to the .env file.')
   .description("Generate a random string.")
   .action(secret.action)
 

lib/detect.js

@@ -0,0 +1,40 @@
+// @ts-check
+import { readFile } from "node:fs/promises"
+import { join } from "node:path"
+
+/**
+ * @typedef {"nextjs" | "express" | "sveltekit"} SupportedFramework
+ */
+
+/**
+ * When this function runs in a framework directory we support,
+ * it will return the framework's name
+ * @returns {Promise<SupportedFramework | "unknown">}
+ */
+export async function detectFramework() {
+  const dir = process.cwd()
+  const packageJsonPath = join(dir, "package.json")
+  try {
+    const packageJson = JSON.parse(await readFile(packageJsonPath, "utf-8"))
+
+    /** @type {SupportedFramework[]} */
+    const foundFrameworks = []
+
+    if (packageJson.dependencies["next"]) foundFrameworks.push("nextjs")
+    if (packageJson.dependencies["express"]) foundFrameworks.push("express")
+    if (packageJson.devDependencies["@sveltejs/kit"])
+      foundFrameworks.push("sveltekit")
+
+    if (foundFrameworks.length === 1) return foundFrameworks[0]
+
+    if (foundFrameworks.length > 1) {
+      console.error(
+        `Multiple supported frameworks detected: ${foundFrameworks.join(", ")}`
+      )
+      return "unknown"
+    }
+    return "unknown"
+  } catch (error) {
+    return "unknown"
+  }
+}

package.json

@@ -30,9 +30,13 @@
   "dependencies": {
     "@inquirer/prompts": "3.3.2",
     "commander": "11.1.0",
+    "prompts": "^2.4.2",
     "yoctocolors": "1.0.0"
   },
   "prettier": {
     "semi": false
+  },
+  "devDependencies": {
+    "@types/node": "^20.12.12"
   }
 }