Helper functions for building express application
Add custom error handlers.
- Syntax:
errorHandler(...customErrorHandlers)
const withCustomErrorHandler: ErrorRequestHandler = (...) => {...};
const withAnotherCustomErrorHandler: ErrorRequestHandler = (...) => {...};
// should always be placed at the very bottom
app.use(
// custom 404 error
wrapper((request) => {
throw new BadRequest(`Cannot ${request.method} ${request.path}`);
}),
// error handlers
errorHandler(withCustomErrorHandler, withAnotherCustomErrorHandler)
);Automatic register controllers on a selected directory.
- Syntax:
registerControllers(absoluteDirPath, basePath, callback)
Rules:
- Filename should be in
[name].controller.{ts|js}format- example:
foo.controller.ts
- example:
- Nested directory is allowed
- If the file named as
index.controller, its base path will be based on its location- example:
src/controllers/foo/bar/index.controller.ts->http://localhost:3001/foo/bar
- example:
const targetDirectory = path.join(__dirname, './controllers');
app.use(registerControllers(targetDirectory));Used in wrapping request handlers that might throw an error, also used in making shorter code by just returning the value itself instead of using the actual response object's method. It also accepts async callbacks. Returns an array, in some cases you can spread it.
- Syntax:
wrapper(...requestHandlers)
const app = express();
app
.get(
'/foo',
wrapper(middlewareThatMightThrowAnError),
wrapper(function () {
...
if (condition) throw SomeError(message)
...
return 'Hello, World!';
}, ...)
);Validate request object's query, body, or params.
- Syntax:
validate(target, dtoClass)- target's valid values are
QUERY,BODY, andPARAMS
- target's valid values are
import { validate, vendors } from '@jmrl23/express-helper';
class UserLoginDto {
@vendors.classValidator.IsString()
@vendors.classValidator.Length(1, 30)
readonly username: string;
@vendors.classValidator.IsString()
@vendors.classValidator.Length(1)
readonly password: string;
}
// usage of `express.json` is required in validating the `request.body`
app.use(express.json());
app.post(
'/user/login',
// validate `request.body`
validate('BODY', UserLoginDto),
wrapper(function (request) {
const data = request.body;
// process data
}),
);Use installed package that may be helpful.
- Available packages
import { vendors } from '@jmrl23/express-helper';
// use `BadRequest` from package `http-errors`
throw new vendors.httpErrors.BadRequest('LOL');