Load a Yaml file, and resolve $ref references

loadYamlWithRefs.mjs

import fs from 'fs'
import path from 'path'
import YAML from 'js-yaml'

/**
 * Process an object with references
 * @param {object} obj - the object to process
 * @param {string} rootFolder - the folder where the yaml file is located
 * @returns {object}
 */
function processObject(obj, rootFolder) {
  for (const prop in obj) {
    if (prop === '$ref') {
      obj = loadYamlWithRefs(obj[prop], rootFolder)
    }
    if (typeof obj[prop] === 'object' && obj[prop].$ref) {
      obj[prop] = loadYamlWithRefs(obj[prop].$ref, rootFolder)
    } else if (Array.isArray(obj[prop])) {
      let arr = obj[prop].reduce((acc, item) => {
        if (typeof item === 'object' && item.$ref) {
          let incoming = loadYamlWithRefs(item.$ref, rootFolder)
          if (Array.isArray(incoming)) acc = acc.concat(incoming)
          else acc.push(incoming)
        } else {
          acc.push(item)
        }
        return acc
      }, [])
      obj[prop] = arr
    }
    if (typeof obj[prop] === 'object') {
      obj[prop] = processObject(obj[prop], rootFolder)
    }
  }
  return obj
}

/**
 * Load a yaml file with references
 * @param {string} file - the file to load
 * @param {string} rootFolder - the folder where the yaml file is located (optional)
 * @returns {object}
 *
 */
export default function loadYamlWithRefs(file, rootFolder = undefined) {
  let filename = file
  if (!rootFolder) {
    rootFolder = path.dirname(file)
    filename = path.basename(file)
  }
  const yamlFile = path.join(rootFolder, filename)

  let doc = YAML.load(fs.readFileSync(yamlFile), { filename: yamlFile })
  doc = processObject(doc, rootFolder)
  return doc
}