Creating node relationships in Gatsby.

gatsby-node.js

const createNodeHelpers = require('gatsby-node-helpers').default;

const { createNodeFactory } = createNodeHelpers({
  typePrefix: 'MyData'
});

const FooNode = createNodeFactory('Foo');
const BarNode = createNodeFactory('Bar');

const foo = { id: 'foo', value: 'foo' };
const bar = [{ id: 0, name: 'Bar1' }, { id: 1, name: 'Bar2' }];

exports.sourceNodes = async ({ actions: { createNode } }) => {
  const fooNode = FooNode(foo);

  await Promise.all(
    bar.map(async data => {
      const barNode = BarNode(data);

      barNode.foo___NODE = fooNode.id;

      createNode(barNode);
    })
  );

  // Can’t create this node until all `barNode`s are created.
  createNode(fooNode);
};