winnow/lib/query/normalize-query-input.js

Apply sql-like filters to GeoJSON

const Joi = require('@hapi/joi')

const featureSchema = Joi.object({
  geometry: Joi.object().allow(null).optional(),
  attributes: Joi.object().optional(),
  properties: Joi.object().optional()
}).or('attributes', 'properties').required().unknown()

function normalizeQueryInput (input) {
  if (isFeatureCollection(input)) {
    return input.features
  }

  if (isFeatureArray(input)) {
    return input
  }

  if (isFeature(input)) {
    return [input]
  }

  throw new Error('Could not normalize query input to feature array')
}

function isFeatureCollection (input = {}) {
  const featureCollectionSchema = Joi.object({
    features: Joi.array().required()
  }).unknown()

  const { error } = featureCollectionSchema.validate(input)

  if (!error && isFeatureArray(input.features)) return true
}

function isFeatureArray (input) {
  if (Array.isArray(input) && input.length === 0) return true

  const featureArraySchema = Joi.array().items(featureSchema).required()

  const { error } = featureArraySchema.validate(input)
  if (!error) return true
}

function isFeature (input) {
  const { error } = featureSchema.validate(input)
  if (!error) return true
}

module.exports = normalizeQueryInput