Querying graph data inside postgres

handlers.js

const { Router } = require('express')
const Step = new Router()

Step.get('/starting_at/:id', async (req, res) => {
  const { rows } = await db.query(`
  SELECT *
  FROM nodes
WHERE
  meta @> '{"starting_states": ["${req.params.id}"]}'
  `)

  res.json({ rows })
})

Step.get('/ending_at/:id', async (req, res) => {
  const { rows } = await db.query(`
  SELECT *
  FROM nodes
WHERE
  meta @> '{"ending_states": ["${req.params.id}"]}'
  `)

  res.json({ rows })
})

Step.get('/graph/:start/:end', async (req, res) => {
  const { rows } = await db.query(`
    WITH RECURSIVE hierarchy AS (
      SELECT *
        FROM nodes
      WHERE meta @> '{"starting_states": ["${req.params.start}"]}'
      UNION ALL
      SELECT N.*
        FROM nodes as N
        JOIN hierarchy as H
          ON (H.meta->'starting_states')::jsonb @> (N.meta->'ending_states')::jsonb
      WHERE H.meta @> '{"ending_states": ["${req.params.end}"]}'
    )

    SELECT *
      FROM hierarchy
    ORDER BY created_at
  `)

  res.json({ rows })
})

schema.sql

CREATE EXTENSION "uuid-ossp";

CREATE TYPE node_type AS ENUM ('link', 'state', 'step', 'modification', 'other');

CREATE TABLE nodes(
  id UUID NOT NULL DEFAULT uuid_generate_v4(),
  title VARCHAR(240) NOT NULL,
  description TEXT,
  type node_type NOT NULL DEFAULT 'other',
  created_at TIMESTAMP NOT NULL DEFAULT NOW(),
  last_updated TIMESTAMP NOT NULL DEFAULT NOW(),
  meta JSONB,
  PRIMARY KEY (id)
);