Managing Deno Imports in Supabase Edge Functions
Deno Uses URL-Based Imports
Unlike Node.js, Deno has no npm install. Imports are ESM URLs:
// Node.js (doesn't work in Deno)
import { createClient } from 'supabase';
// Deno (correct)
import { createClient } from 'https://esm.sh/@supabase/supabase-js@2';
Pin Your Versions
// ❌ Unpinned — will break on next major release
import { Hono } from 'https://deno.land/x/hono/mod.ts';
// ✅ Pinned
import { Hono } from 'https://deno.land/x/hono@v4.7.0/mod.ts';
The @latest alias on deno.land resolves dynamically. An unpinned import that works today can silently break tomorrow.
Centralize with deno.json
Put a deno.json in supabase/functions/ to alias all imports:
{
"imports": {
"@supabase/supabase-js": "https://esm.sh/@supabase/supabase-js@2.49.4",
"hono": "https://deno.land/x/hono@v4.7.0/mod.ts",
"hono/cors": "https://deno.land/x/hono@v4.7.0/middleware/cors/index.ts"
}
}
Each Edge Function imports by alias:
import { createClient } from '@supabase/supabase-js';
import { Hono } from 'hono';
Version upgrades: change one line in deno.json, all EFs update.
Shared Utilities with _shared/
Avoid repeating Supabase client initialization in every EF:
// supabase/functions/_shared/supabase.ts
import { createClient } from '@supabase/supabase-js';
export function getClient(req: Request) {
const auth = req.headers.get('Authorization')!;
return createClient(
Deno.env.get('SUPABASE_URL')!,
Deno.env.get('SUPABASE_ANON_KEY')!,
{ global: { headers: { Authorization: auth } } }
);
}
export function getAdminClient() {
return createClient(
Deno.env.get('SUPABASE_URL')!,
Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!
);
}
Keep deno lint at Zero
deno lint runs in CI. Common violations to avoid:
// ❌ prefer-const — reassigned never → must be const
let count = 0;
// ✅
const count = 0;
// ❌ no-explicit-any
function process(data: any) {}
// ✅ use unknown and narrow
function process(data: unknown) {
if (typeof data === 'string') { ... }
}
Run after every EF change:
deno lint supabase/functions/
import_map.json vs deno.json
Older Supabase projects use import_map.json. Migrate to deno.json:
mv supabase/functions/import_map.json supabase/functions/deno.json
# Wrap content: { "imports": { ...same content... } }
Summary
| Concern | Solution |
|---|---|
| Version drift | Pin with @x.y.z in every URL |
| Many EFs same imports |
deno.json imports aliases |
| Repeated client init |
_shared/supabase.ts utility |
| CI lint failures |
deno lint after every EF edit |
Good import hygiene means zero "works locally, breaks in CI" surprises.
Building in public: https://my-web-app-b67f4.web.app/
