schema-guard

Create lightweight runtime type guards from a plain object schema

Install

npm install schema-guard

Usage

import schemaGuard from 'schema-guard';

const isUser = schemaGuard({
	name: 'string',
	age: 'number',
	email: 'string?',
	tags: 'string[]',
	active: 'boolean',
});

isUser({name: 'Alice', age: 30, tags: ['admin'], active: true});
//=> true

isUser({name: 123});
//=> false

API

schemaGuard(schema)

Returns a type guard function (value: unknown) => boolean.

schema

Type: object

An object mapping property names to type strings.

Supported types: string, number, boolean, bigint, symbol, function, object, array.

Use ? suffix for optional fields (accepts undefined and null):

{email: 'string?'}

Use [] suffix for typed arrays:

{tags: 'string[]'}

Only declared keys are checked. Extra properties on the input value do not cause failure.

Limitations: Nested object validation is not supported. Use 'object' to check that a property is an object, but its shape will not be validated.

Related

• is-runtime - Detect the current JavaScript runtime environment

License

MIT