gearworks-validation

A TypeScript wrapper around the Joi package, providing typed object validation for Gearworks apps. Gearworks is the best way to get started with building Shopify applications!

Installing

You can install this package from NPM with the NPM CLI or with Yarn (recommended):

# With NPM
npm install gearworks-validation --save

# With Yarn
yarn add gearworks-validation

Importing

You can import the validators either one function at a time, or all at once, via require or TypeScript's import:

// Import all functions
import * as gwv from "gearworks-validation";

// Import just one function
import { strings } from "gearworks-validation";

// Import all functions via Node's require:
const gwv = require("gearworks-validation");

// Import just one function via Node's require:
const strings = require("gearworks-validation").strings;

Usage

Most of the functions are straightforward and self-explanatory. Where this package really shines is when using the functions that provide intellisense for TypeScript types: object, numbers, onlyStrings, onlyStringsOrEmpty, and array.

import * as gwv from "gearworks-validation";

type MyString = "hello" | "world";

type MyNumber = 1 | 2 | 3;

interface MyType {
    foo: string;
    bar: number;
    baz: boolean;
    bat: MyString[];
    bang: MyNumber[];
}

const schema = gwv.object<MyType>({
    // We now have intellisense on MyType property names.
    foo: gwv.string().required(),
    bar: gwv.number(),
    baz: gwv.boolean(),
    bat: gwv.onlyStrings<MyString>("hello", "world" /* And we have intellisense on these strings. */),
    bang: gwv.numbers<MyNumber>(1, 2, 3 /* And these numbers! */)
})

Why?

Joi is a great package, which I use liberally throughout Gearworks and my own custom Shopify apps, but it has one big pitfall that we can easily fall into when working with plain JS packages: there's no type intellisense for the objects that I'm validating!

I would have zero intellisense for validating an object with plain Joi; I'd have to open my interface definition in a side-by-side window to make sure I was validating all of the properties I needed to validate. Worse, though, was that I wouldn't have any warnings or compiler errors when I changed a property on my interfaces. I'd just have to cross my fingers and hope that I updated all occurrences.

That problem is now solved with gearworks-validation.