Function processTree

dadi/lib/fields/reference.js:329–387

(tree, path = [])

  // processes it recursively, running the `find` method in the
  // appropriate models.
  const processTree = (tree, path = []) => {
    let queue = Promise.resolve({})

    Object.keys(tree).forEach(key => {
      const canonicalKey = key.split('@')[0]

      queue = queue.then(query => {
        if (
          tree[key] &&
          typeof tree[key] === 'object' &&
          !isOperatorQuery(tree[key])
        ) {
          return processTree(tree[key], path.concat(key)).then(result => {
            return Object.assign({}, query, {
              [canonicalKey]: result
            })
          })
        }

        return Object.assign({}, query, {
          [canonicalKey]: tree[key]
        })
      })
    })

    const firstKey = Object.keys(tree)[0]
    const modelChain = createModelChain(this, path.concat(firstKey))
    const model = modelChain && modelChain[modelChain.length - 1]

    return queue.then(query => {
      if (path.length === 0) {
        return query
      }

      // This is a little optimisation. If the current query didn't yield
      // any results, there's no point in processing any nodes to the left
      // because the result will always be an empty array.
      Object.keys(query).forEach(field => {
        if (
          query[field].$containsAny &&
          query[field].$containsAny.length === 0
        ) {
          return {
            $containsAny: []
          }
        }
      })

      return model
        .find({
          query
        })
        .then(({results}) => {
          return {
            $containsAny: results.map(item => item._id.toString())
          }
        })
    })