ts-blaze

This library makes type-safe usage of objects from unknown origin (-> api payloads, events, parsed files etc.) a blast. It does so by generating typeguards for the validators you create.

Usage

import { object, string, number, ensure } from 'ts-blaze'

const isHuman = object({
  name: string(),
  age: number()
})
type Human = InferValidatorType<typeof isHuman>

export const onlyAcceptHumans = (payload: any): Promise<Human> => {
  const human = ensure(payload, isHuman) // throws if payload doesn't match schema

  console.log(`Creating human with name "${human.name}".`) // your IDE/Editor can auto complete this
  return db.createHuman(payload)
}

export const gracefullyHandleBadInput = (payload: any): Promise<Human | void> => {
  if (isHuman(payload)) {
    return db.createHuman(payload) // no typescript error
  }

  console.warn('Did not receive a human')
  return Promise.resolve()
}

Details

The object validator matches standard TypeScript behaviour, i.e. it doesn't complain about additional keys.

Provided Types

Currently the following types are supported: object, array, string, number, oneOf([ ...unionTypes ]), string literal (using string('literal')) and number literal (using number(1)).

Define Your Own

import type { Validator } from 'ts-blaze'

export interface UUIDValidator extends Validator<string> {
  
}

const createUuidValidator = (): StringValidator => {
  const validateUuid = (value: any): value is string => {
    return typeof value === 'string' &&
      isUuid(value)
  }

  return validateUuid
}

export default createUuidValidator

Options

Currently there are no additional validation options implemented. The api is going to be number(...).min(0).integer(). Feel free to open PRs with implementations.

Error Messages

At the moment there are no plans to implement validation error messages. However I'm open to ideas so feel free to create issues and PRs for this as well.