@valfuse-node/validation

Framework-agnostic schema validation and value transformation for browser and server applications. It has no React, Vue, Express, or other runtime framework dependency.

npm install @valfuse-node/validation

Define and validate a schema

import { createSchema, t, transformValues, validateSchema } from "@valfuse-node/validation";

const createUserSchema = createSchema({
  email: {
    type: "string",
    transform: t.pipe(t.trim, t.toLowerCase),
    rules: [
      { name: "required", error: { message: "Email is required." } },
      { name: "email", error: { message: "Enter a valid email." } },
    ],
  },
  age: {
    type: "number",
    transform: t.toInteger,
    rules: [{ name: "min", value: 18, error: { message: "Must be 18 or older." } }],
  },
});

const values = transformValues(createUserSchema, {
  email: "  [email protected] ",
  age: "25",
});
const errors = validateSchema(createUserSchema, values);
// values: { email: "[email protected]", age: 25 }
// errors: {}

validateSchema returns the first error for each invalid field. Its rules cover strings, numbers, booleans, arrays, objects, and cross-field checks. t exports built-in transforms such as trim, toLowerCase, toInteger, and toNumber.

Use with forms or backend APIs

React and Vue adapters use this package for local field validation. Express middleware uses it to validate parsed request data. Applications may define a different schema for a form and an API request when their value shapes or rules differ; both schemas can use the same validation engine.

import { createSchema } from "@valfuse-node/validation";
import { validateBody } from "@valfuse-node/express";

const createUserRequestSchema = createSchema({
  email: {
    type: "string",
    rules: [{ name: "required", error: { message: "Email is required." } }],
  },
});

app.post("/users", validateBody(createUserRequestSchema), createUserHandler);

Validation is synchronous and does not check database-backed rules such as email uniqueness. Keep those checks in the backend service or domain layer.

Compatibility

@valfuse-node/form continues to re-export the validation API for existing consumers. New code should import schema, rule, transformer, and validation APIs from this package.

License

MIT