harissa
v0.16.0
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Harissa
The modern toolkit for type-safe express apps
Harissa provides a set of helpers to make working with express.js
in more enjoyable, secure, and rapid.
Harissa is explicitly not a framework. It merely provides a handful of tools to make common tasks like validation, type-safety and async first-class citizens with express.
npm i harissa
The goal of harissa is to provide a slim – but powerful – set of express utilities, and nothing more.
[!IMPORTANT]
Harissa is currently used in production internally, but is not recommended for large scale projects just yet - expect some API tweaks
Route
The route
utility is the centerpiece of harissa. It provides a simple, chainable trpc-like interface for defining endpoints in a more declarative fashion. Consequently, routes are easily composed and highly declarative, enabling the out-of-the-box schema definitions (OpenAPI and typescript).
A simple example might look like:
const userRoute = route("/user/:id")
.method("post")
.body(z.object({ field: z.string() }))
.handle((req, res, next) => req.body.field);
Or a more complete example:
const userRoute = route("/user/:id")
.use(...middleware)
.method("post")
.params(ParamSchema)
.body(BodySchema)
.output(OutputSchema)
.headers(HeaderSchema)
.handle(async (req) => req.user);
[!TIP] Most popular validation libraries are supported by Harissa
This returns a regular express route handler/middleware, designed to be used as per normal:
app.route(
"/user/:id",
route().handle(async (req) => {})
);
Or many routes can be registered at once:
const appRoutes = [userRoute, postsRoute, authRoute];
registerRoutes(app, appRoutes);
Composability
Routes can be chained for better composability:
const authedRoute = route().use<{ userId: string }>(hasUserMiddleware);
const getUserRoute = authedUserRoute
.path("/user/me")
.method("get")
.handle((req) => typeof req.userId === "string"); // -> true
Paths and middleware can be appended:
Paths:
const postRoute = route("/post");
const getAllPostsRoute = postRoute.path("/all").method("get");
const deletePostRoute = postRoute.path("/:postId").method("delete");
Middleware:
const withFoo = (x: any) =(req, res, next) => {
console.log(x)
req.foo = x
next()
}
route()
.use<{ foo: string }>(withFoo("foo"))
.use<{ foo: number }>(withFoo(1))
.use<{ foo: boolean }>(withFoo(true))
.handle((req) => typeof req.foo === "boolean"); // -> true
// 3x middleware are called:
// Log: foo
// Log: 1
// Log: true
Whereas schema override eachother:
route()
.body(CreateUserBody) // <- This one is overridden
.body(CreatePostBody);
Client
On the client side, Harissa provides a slim, unopinionated utility for type-safe API calls, if you're into that sort of thing.
// backend.ts
import { H } from "harissa";
const AppRoutes = [userRoute, authRoute, ...otherRoutes];
export type App = H.Infer<typeof AppRoutes>;
// client.ts
import { createTypedClient } from "harissa/client";
export const api = createTypedClient<App>({
fetcher: (
{ path, method, body, params, query },
opts?: AxiosOptions // Any arbitrary type
) => {
// TODO: Call your API with axios, fetch, etc.
},
});
api("/user/:id").get(
{ params: { id: "..." }, ...etc }, // Config derived from API schema
{ ...myOptions } // Type inferred from `opts` above
);
You can also infer specific endpoint information, fairly egonomically.
type GetUserEndpoint = H.Endpoint<App, "/user/:id", "get">;
type GetUserParams = GetUserEndpoint["params"];
type GetUserResponse = GetUserEndpoint["output"];
export const getUser = (
params: GetUserEndpoint["params"]
): Promise<GetUserEndpoint["output"]> => api("/user/:id").get({ params });
Primitives
Several lower-level primitives are exposed.
Exceptions
createHttpException
can be used to create common HTTP exceptions.
export class NotFoundException extends createHttpException("NOT_FOUND") {}
throw new NotFoundException("User not found");
// status = 404, name = "NOT_FOUND", message = "User not found"
Handlers
Less feature-full handler primitives are exposed, providing async
and raw return functionality.
import {
middlewareHandler,
routeHandler,
errorHandler
} from "harissa"
app.use(
middlewareHandler((req, res, next) => {
req.foo = "bar";
return next();
})
);
app.get(
"/",
routeHandler((req, res, next) => {
return "Some data";
})
);
app.use(errorHandler(err, req, res, next) => {
console.error(err)
res.status(500)
return err
})
OpenAPI
[!WARNING]
OpenAPI support is currently experimental and also varies according to validation library
We can create OpenAPI routes given our express app. While harissa route
s with schema information are encouraged, any express route can be included in our api spec.
const spec = createOpenApiSpec(app, {
/** Options */
});
// Optionally: Add/remove/modify spec if you wish
app.get("/openapi.json", (req, res) => {
res.json(spec.asJson());
});
Currently supported schema with OpenAPI schema generation:
- ✅ Zod
[!TIP] If you'd like support for your validation library added, please create a new issue.