Tschema

Tschema is simple and fastest static type checker for Node.js.

Why it's the Fastest?

Because Tschema compiles scheme validation code into single static function - containing only if statements.
So Tschema doesn't parse the schema at runtime. It only consumes O(1) on validation time.

Install

npm install tschema

Example

const { Schema, Optional } = require('tschema');

const User = new Schema({
  name: String,
  age: Number,
  friends: [String],
  info: {
    createdAt: Date,
    lastLoginedAt: Optional(Date),
  },
});

User.validate({ name: 'John', age: 20, friends: ['foo', 'bar'], info: { createdAt: Date.now() } });

Documentations

Defining a Schema

new Schema(schema, options)

You can create schema using tschema.Schema class.

• schema: any type or object.

  Available types are:

  • Number String Boolean - primitives
  • Array - any array
  • Object - any object
  • Date
  • Any - anything
  • Optional(Type) - optional (nullable)
  • [Type] - array of some type
  • { ... } - nested object
  • Schema - another schema

  Instead of giving constructors or Optional, you can define schema using Flow style.

  const User = new Schema({
    name: 'string',
    age: 'number',
    friends: 'string[]',
    createdAt: '?date',
  });

  • 'number', 'string', 'boolean' - primitives
  • 'array', 'object', 'date', 'any'
  • '?type' - optional
  • 'type[]' - array of some type

• options: You can pass some options if you want. These options will be

  • errorProducer: The error function.
  • dateParser: Date parser function.

Customizing a Schema

Change error behavior

In default, Schema#validate will throw an Error if given value is invalid.

errorProducer: (field, type) => `throw Error('${field} is not a ${type}.')`

You can change this behavior by passing your own errorProducer to options.
For example, if you want to return some object if Schema#validate fails, you need to do like this:

const User = new Schema({ ... }, {
  errorProducer: (field, type) => ({ error: { name: field, tobe: type } })
});

Use custom date parser

In default, Tschema parses Date type using new Date.

dateParser: (value) => new Date(value)

You can replace this parser by passing your own dateParser to options.

TODO

• Named Schema for self-embedding (ex: User = new Schema('User', { author: 'User' }))
• Strict mode (fails at verify if given value has fields undefined on schema)
• Integration with ORM/ODM libraries (sequelize, mongorito, mongoose, ...)
• TypeScript, Flow support

License: MIT