What

A toy example of graphql. Sources:

• https://www.youtube.com/watch?v=ZQL7tL2S0oQ
• https://www.youtube.com/playlist?list=PL4cUxeGkcC9iK6Qhn-QLcXCXPQUov1U7f
• https://fullstackopen.com/en/part8

... this is a work in progress ... Missing:

• Add some Frontend
• Use a Database

Background

In node.js there is no concept of virtual environment. We just install all packages to the base and when changing to a new project just change to the version of that package.

There are two main package providers:

• npm
• yarn

In both cases, the file package.json is the equivalent to setup.py in Python. It specifies the package constraints e.g. "^2.0.16" means ">=2.0.16 <3.0.0".

How to install packages with yarn

To recreate what's needed for this toy project:

brew install yarn
yarn install

In general, we could do like

yarn add express express-graphql graphql
yarn add --dev nodemon

This would generate the file yarn.lock which is the analogous to requirements.txt in Python, and these packages to package.json.

How to run the server

yarn run start

and go to localhost:5000/graphiql, or

yarn run devStart

if you want to reload the server when doing changes to code.

Example queries and mutations

query Queries{
  authors {
    #id,
    name,
    #num_books,
    yearBorn,
    age,
    #books {
    #  name
    #},
  },
  #author(id: "0770663089") {
  #  name
  #},
  #books {
  #  id,
  #  name,
  #  year,
  #  author {
  #    name
  #  }
  #},
  #books {
  #  id,
  #},
  #book(id: "1297929770") {
  #  name,
  #  year,
  #  author {
  #  	name,
  #	}
  #},
  #books_where(id: "1297929770", year: 1942) {
  #  name,
  #  author {
  #    name
  #  },
  #  year
  #},
}

mutation addMarc{
  addAuthor(
    name: "Marc",
    yearBorn: 1988,
  ){
    id,
    name,
    yearBorn,
    yearDeath
  }
}