Integrate Jest tests for TypeScript definitions

[akazakou]

Description

Here I've done a kludge to import type definitions without rewriting exists type definitions.

I've added Triple-Slash Directive to allow import of fastest-validator types.

/// <reference path="../../../index.d.ts" />

Next, I've imported default export from fastest-validator definition package

import ValidatorType from 'fastest-validator';

And the last one I've imported from javascript file default export and assigned to this imported variable, exported from 'fastest-validator' definition type.

const Validator: typeof ValidatorType = require('../../../index');

Now constant Validator have a type named as ValidatorType that actually Validator class.

Changelog

• Added @types/jest, rollup-plugin-copy and ts-jest dev dependencies
• Added copying index.d.ts file into dist folder
• Integrated TypeScript test via ts-jest support

Now you no need dedicated test:ts npm job. You will be enough to run test job and it will test Javascript and Typescript files at the same time.

[coveralls]

Coverage remained the same at 100.0% when pulling 9a9df8f on akazakou:feature/next-typescript-integration-for-jest into 3442228 on icebob:next.

[icebob]

Awesome job @akazakou! Thank you very much and thank you for your quick job!