TypeScript JSON Validator

Automatically generate a validator using JSON Schema and AJV for any TypeScript type.

Usage

Define a type in src/Example.ts, e.g.:

export default interface ExampleType {
	value: string;
	/**
	 * @TJS-format email
	 */
	email?: string;
	/**
	 * @default 42
	 */
	answer: number;
}

To generate a validator, run:

npx @rkesters/typescript-json-validator src/Example.ts ExampleType

This will generate src/Example.validator.ts, which you can use:

import { readFileSync } from 'fs';
import validate from './Example.validator.ts';

const value: unknown = JSON.parse(readFileSync(process.argv[2], 'utf8'));

// this will through a clear error if `value` is not of the
// correct type. It will also fill in any default values
const validatedValue = validate(value);

console.log(validatedValue.value);

Note that types will be validated automatically, but you can also use annotations to add extra runtime checks, such as e-mail formatting. For annotations see: https://github.com/YousefED/typescript-json-schema#annotations

CLI Docs

Usage: typescript-json-schema <path-to-typescript-file> <type>

Options:
      --help              Show help                                    [boolean]
      --version           Show version number                          [boolean]
      --refs              Create shared ref definitions.
                                                       [boolean] [default: true]
      --topRef            Create a top-level ref definition.
                                                      [boolean] [default: false]
      --noExtraProps      Disable additional properties in objects by default.
                                                       [boolean] [default: true]
      --propOrder         Create property order definitions.
                                                       [boolean] [default: true]
      --strictNullChecks  Make values non-nullable by default.
                                                       [boolean] [default: true]
      --id                ID of schema.                   [string] [default: ""]
      --uniqueItems       Validate `uniqueItems` keyword
                                                       [boolean] [default: true]
      --unicode           calculate correct length of strings with unicode pairs
                          (true by default). Pass false to use .length of
                          strings that is faster, but gives "incorrect" lengths
                          of strings with unicode pairs - each unicode pair is
                          counted as two characters.   [boolean] [default: true]
      --nullable          support keyword "nullable" from Open API 3
                          specification.               [boolean] [default: true]
      --format            formats validation mode ('fast' by default). Pass
                          'full' for more correct and slow validation or false
                          not to validate formats at all. E.g., 25:00:00 and
                          2015/14/33 will be invalid time and date in 'full'
                          mode but it will be valid in 'fast' mode.
                                     [choices: "fast", "full"] [default: "fast"]
      --coerceTypes       Change data type of data to match type keyword. e.g.
                          parse numbers in strings    [boolean] [default: false]
      --collection        Process the file as a collection of types, instead of
                          one single type.            [boolean] [default: false]
  -o, --out               name of output, optional                      [string]

License

MIT