diff --git a/build.js b/build.js
index de51316..1b2dce6 100755
--- a/build.js
+++ b/build.js
@@ -17,7 +17,7 @@ esbuild
     packages: 'external'
   })
   .then(() => {
-    const packageJson = JSON.stringify({ type: 'module' })
+    const packageJson = JSON.stringify({type: 'module'})
     fs.writeFileSync(`${__dirname}/lib/esm/package.json`, packageJson, 'utf8')
 
     console.log('esm build success.')
diff --git a/justfile b/justfile
index 509adc6..9ba1f1f 100644
--- a/justfile
+++ b/justfile
@@ -18,3 +18,6 @@ emit-types:
 publish: build
     emit-types
     npm publish
+
+format:
+    prettier --plugin-search-dir . --write .
\ No newline at end of file
diff --git a/nip06.test.js b/nip06.test.js
index 1e28412..643e705 100644
--- a/nip06.test.js
+++ b/nip06.test.js
@@ -4,12 +4,16 @@ const {nip06} = require('./lib/nostr.cjs')
 test('generate private key from a mnemonic', async () => {
   const mnemonic = 'zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong'
   const privateKey = nip06.privateKeyFromSeedWords(mnemonic)
-  expect(privateKey).toEqual('c26cf31d8ba425b555ca27d00ca71b5008004f2f662470f8c8131822ec129fe2')
+  expect(privateKey).toEqual(
+    'c26cf31d8ba425b555ca27d00ca71b5008004f2f662470f8c8131822ec129fe2'
+  )
 })
 
 test('generate private key from a mnemonic and passphrase', async () => {
   const mnemonic = 'zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong'
   const passphrase = '123'
   const privateKey = nip06.privateKeyFromSeedWords(mnemonic, passphrase)
-  expect(privateKey).toEqual('55a22b8203273d0aaf24c22c8fbe99608e70c524b17265641074281c8b978ae4')
+  expect(privateKey).toEqual(
+    '55a22b8203273d0aaf24c22c8fbe99608e70c524b17265641074281c8b978ae4'
+  )
 })
diff --git a/nip06.ts b/nip06.ts
index 037cb9e..6d37860 100644
--- a/nip06.ts
+++ b/nip06.ts
@@ -7,7 +7,10 @@ import {
 } from '@scure/bip39'
 import {HDKey} from '@scure/bip32'
 
-export function privateKeyFromSeedWords(mnemonic: string, passphrase?: string): string {
+export function privateKeyFromSeedWords(
+  mnemonic: string,
+  passphrase?: string
+): string {
   let root = HDKey.fromMasterSeed(mnemonicToSeedSync(mnemonic, passphrase))
   let privateKey = root.derive(`m/44'/1237'/0'/0/0`).privateKey
   if (!privateKey) throw new Error('could not derive private key')
diff --git a/package.json b/package.json
index 041565e..71b86ba 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,9 @@
     "type": "git",
     "url": "https://github.com/nbd-wtf/nostr-tools.git"
   },
-  "files": ["./lib/**/*"],
+  "files": [
+    "./lib/**/*"
+  ],
   "types": "./lib/index.d.ts",
   "main": "lib/nostr.cjs.js",
   "module": "lib/esm/nostr.mjs",