chore: nudge to install the @netlify/functions package

src/lib/functions/check-tsconfig-for-v2-api.mjs

@@ -1,12 +1,13 @@
 // @ts-check
 import { existsSync } from 'fs'
 import { writeFile } from 'fs/promises'
+import { createRequire } from 'module'
 import { join } from 'path'
 
 import { parseTsconfig } from 'get-tsconfig'
 import terminalLink from 'terminal-link'
 
-import { NETLIFYDEVLOG, chalk, log } from '../../utils/command-helpers.mjs'
+import { NETLIFYDEVLOG, NETLIFYDEVWARN, chalk, log } from '../../utils/command-helpers.mjs'
 
 /**
  * The `tsconfig.json` we are going to write to the functions directory.
@@ -44,6 +45,16 @@ export async function checkTsconfigForV2Api(config) {
     return
   }
 
+  try {
+    const require = createRequire(config.functionsDir)
+    require.resolve('@netlify/functions')
+  } catch {
+    log(
+      `${NETLIFYDEVWARN} Please install the ${chalk.dim(
+        '@netlify/functions',
+      )} package to get a better typed experience!`,
+    )
+  }
   const tsconfig = join(config.functionsDir, 'tsconfig.json')
 
   if (existsSync(tsconfig)) {