How to use the mongo-query-to-postgres-jsonb.pathToText function in mongo-query-to-postgres-jsonb

async function crud(socket, reqId, databaseName, commandName, doc, build) {
  const normalizedCommandName = commandName.toLowerCase()
  let rawCollectionName = doc[commandName] || doc[normalizedCommandName]
  let collectionName = '"' + rawCollectionName + '"'
  if (commandName === 'distinct') {
    if ((doc.query && typeof doc.query !== 'object') || typeof doc.key !== 'string') {
      socket.write(build(reqId, { ok: 0, errmsg: '"query" had the wrong type. Expected object or null,', code: 14 }, {}))
      //throw new Error('\\"query\\" had the wrong type. Expected object or null, found ' + typeof doc.query)
      return true
    }
    const filter = doc.query || {}
    let where = safeWhereConversion(filter, rawCollectionName)
    const distinctField = mongoToPostgres.pathToText(['data'].concat(doc.key.split('.')), false)
    const arrayCondition = `jsonb_typeof(${distinctField})='array'`
    const query1 = `SELECT DISTINCT ${distinctField} AS data FROM ${collectionName} WHERE ${where} AND NOT ${arrayCondition}`
    const query2 = `SELECT DISTINCT jsonb_array_elements(${distinctField}) AS data FROM ${collectionName} WHERE ${where} AND ${arrayCondition}`
    const query = `${query1} UNION ${query2}`
    const res = await tryOrCreateTable(async () => await doQuery(databaseName, query), databaseName, collectionName)
    const rows = res.rows.map((row) => convertToBSON(row.data))
    debug('pgmongo:rows')(rows)
    const data = { values: rows, ok: 1 }
    socket.write(build(reqId, data, {}))
    return true
  }
  if (commandName === 'find') {
    const filter = doc.filter
    const where = safeWhereConversion(filter, rawCollectionName)
    let select = mongoToPostgres.convertSelect('data', doc.projection)

const pgPath = keys.map(function(key) {
        const path = ['data'].concat(key.split('.'))
        return mongoToPostgres.pathToText(path, false)
      }).join(', ')
      let indexQuery = `CREATE INDEX "${index.name}" ON ${collectionName} USING gin ((${pgPath}));`