Units

An experimental collection of GraphQL Types to represent units of measurement in various systems.

Getting Started

Install

npm i -D @grapheng/units

Use

Output types: Minimal Example:

import { Distance, Rounding } from "@grapheng/units";

const schema = makeExecutableSchema({
  typeDefs: gql`
    ${Distance.GraphQL.outputType.typeDefs}
    ${Rounding.typeDefs}

    type Query {
      myQuery: DistanceOutput!
    }
  `,
  resolvers: {
    DistanceOutput: Distance.GraphQL.outputType.resolvers,
    Query: {
      myQuery: () => ({ meters: 3 })
    }
  }
});

For Input types, writing

import { Distance } from "@grapheng/units";

gql`
  ${Distance.GraphQL.inputType.typeDefs}
`;

into your schema is enough to start using DistanceInput anywhere. However, the library also exports a convenience function with each module to help use the type in your code.

Below is an example that offers a flexible API for input (for example { feet: 4, inches: 2 }) but uses this function to convert it ultimately to millimeters (4 feet 2 inches => 1270 millimeters)

import { Distance } from "@grapheng/units";

const resolvers = {
  Mutations: {
    addPieceOfLumberToInventory: (source, args, context) =>
      context.DB.addPieceOfLumberToInventory(
        args.boardType,
        Distance.convertInput(args.boardLength).millimeters
      )
  }
};

Experiment

cd into this package and npm run start then open http://localhost:4000/graphql in your browser

Further Development TODOs

Bugs

• fix moment library drift (1000 years -> milliseconds -> years)

General Improvements

• make types better

Implement new types

• location -> tries to go out and get stuff async
• price / or specific types like dollar?

Complete API Re-Design:

• export each package individually?
• investigate making graphql queries completely flexible (e.g. fuel efficiency -> miles per gallon, or km per milliliter, etc.)