@tezx/validate

Schema validation middleware for TezX framework. Supports Zod, AJV, Joi, or any custom schema adapter. Automatically parses request data (body, query, params) and sets ctx.validated for downstream handlers.

Features

• Works with TezX middleware.
• Supports async validation.
• Compatible with Zod, AJV, Joi, or any custom adapter.
• Optional error handler for validation failures.
• Optional data transformation after validation.
• Supports parsing of json, text, or formData request bodies.

Installation

npm install @tezx/validate
# or
yarn add @tezx/validate

Usage

Import

import { validate, SchemaAdapter } from "@tezx/validate";
import { z } from "zod"; // or import AJV/Joi

Basic Example with Zod

const userSchema: SchemaAdapter = {
  validate: async (data) =>
    z.object({
      username: z.string().min(3),
      password: z.string().min(6)
    }).parseAsync(data)
};

app.use(
  "/login",
  validate({ adapter: userSchema }),
  (ctx) => {
    // ctx.validated contains validated data
    ctx.json({ success: true, user: ctx.validated });
  }
);

Using AJV

import Ajv from "ajv";

const ajv = new Ajv();
const schema = {
  type: "object",
  properties: {
    username: { type: "string", minLength: 3 },
    password: { type: "string", minLength: 6 }
  },
  required: ["username", "password"],
  additionalProperties: false
};

const ajvAdapter: SchemaAdapter = {
  validate: async (data) => {
    const valid = ajv.validate(schema, data);
    if (!valid) throw new Error(JSON.stringify(ajv.errors));
    return data;
  }
};

app.use("/login", validate({ adapter: ajvAdapter }));

Using Joi

import Joi from "joi";

const joiSchema = Joi.object({
  username: Joi.string().min(3).required(),
  password: Joi.string().min(6).required()
});

const joiAdapter: SchemaAdapter = {
  validate: async (data) => {
    const { error, value } = joiSchema.validate(data);
    if (error) throw error;
    return value;
  }
};

app.use("/login", validate({ adapter: joiAdapter }));

Options

| Option | Type | Default | Description | | | | ----------- | -------------------------------------------- | ------- | --------------------------------------------- | -------- | ------------------------------ | | adapter | SchemaAdapter | — | Schema validator implementation | | | | onError | (err: Error, ctx: Context) => Response | — | Custom error handler | | | | source | "body" | "query" | "params" | "body" | Source of data to validate | | transform | (data: any) => any | — | Optional function to transform validated data | | | | parseBody | "json" | "text" | "formData" | "json" | Parser method for request body |

Error Handling

By default, validate will throw a Error with status 400 on validation failure. You can provide onError to customize the response:

validate({
  adapter: userSchema,
  onError: (err, ctx) => ctx.json({ success: false, message: err.message }, 422)
});

TypeScript Support

ctx.validated is automatically typed as any, but you can narrow it by providing generic types:

validate<{ username: string; password: string }>({
  adapter: userSchema
});

Custom Adapters

You can implement any schema library by creating a simple adapter:

const customAdapter: SchemaAdapter = {
  validate: async (data) => {
    if (!data.username) throw new Error("Missing username");
    return data;
  }
};

app.use(validate({ adapter: customAdapter }));