NestJS bcryptjs Setup

Use this workflow to add reusable one-way secret hashing with bcryptjs.

Prerequisites

• NestJS backend with AppModule and src
• Node.js 20+ for modern Nest projects
• @nestjs/config available so SALT_ROUNDS can be read from environment

Preflight checks

1. Confirm target is a NestJS backend root containing package.json, src/main.ts, and src/app.module.ts.
2. Confirm package manager from lockfile:
   • package-lock.json -> use npm
   • pnpm-lock.yaml -> use pnpm
   • yarn.lock -> use yarn
3. If required files are missing, stop and report the exact missing path before editing.

Install dependencies

If @nestjs/config is missing, install it first.

npm install @nestjs/config

Install bcrypt packages from project root:

npm install bcryptjs
npm install -D @types/bcryptjs

Equivalent commands may be used for pnpm or yarn, but keep dependency intent identical.

Configure SALT_ROUNDS

Add SALT_ROUNDS to .env:

• Production: 10-12
• Tests/local fast feedback: 4-8

Example:

SALT_ROUNDS=10

If not already present, wire global config in AppModule:

ConfigModule.forRoot({ isGlobal: true })

If ConfigModule.forRoot({ isGlobal: true }) already exists, do not duplicate it.

Add EncryptionService

Implement EncryptionService from reference.md with these rules:

1. Inject ConfigService.
2. Parse and validate SALT_ROUNDS once in the constructor.
3. Expose hash(plain: string): Promise<string>.
4. Expose verify(plain: string, hashed: string): Promise<boolean>.
5. Use only one-way terms (hash and verify), not encrypt/decrypt names.
6. Throw clear startup errors when SALT_ROUNDS is missing or out of accepted range.

Add EncryptionModule

Create a global module from reference.md that:

• imports ConfigModule
• provides EncryptionService
• exports EncryptionService

Register EncryptionModule in AppModule.imports.

Optional env helper

Use addEncryptionEnvVariables from reference.md if the project generates .env or .env.example files programmatically.

Suggested file layout

• src/libs/encryption/encryption.service.ts
• src/libs/encryption/encryption.module.ts
• src/libs/encryption/encryption.utils.ts (optional)
• src/libs/encryption/index.ts

Verification

1. Run backend checks from project root:

npm run build
npm run test

2. Verify hashing flow:
   • verify(plain, await hash(plain)) returns true.
   • verify('wrong', await hash('correct')) returns false.
3. Verify config guardrails:
   • App boots with valid SALT_ROUNDS.
   • Missing or invalid SALT_ROUNDS fails fast with a clear startup error.
4. If any check fails, report exact failing command or assertion and stop before claiming completion.

Checklist

• Confirm NestJS project root and package manager
• Install bcryptjs and @types/bcryptjs
• Ensure ConfigModule.forRoot({ isGlobal: true }) is configured
• Add SALT_ROUNDS to .env
• Add EncryptionService and EncryptionModule from reference.md
• Import EncryptionModule in AppModule
• Run build and tests, then verify hash/compare flow end to end

Additional resources

• Full code snippets: reference.md