rosid/src/validate.js

'use strict'

const path  = require('path')
const async = require('async')

/**
 * Parse and validate a route.
 * @public
 * @param {Object} route - A single route configuration.
 * @returns {Object} route - A single validated route configuration.
 * @throws {Error}
 */
const _route = function(route) {

	// Copy object to prevent changes by reverence
	route = Object.assign({}, route)

	// Check if route has a name
	// The name is required to output informative messages and errors
	if (route.name==null || route.name==='') throw new Error('Missing name property in route')

	// Check if route has a path and a handler
	if (route.path==null)    throw new Error(`Missing path property in route '${ route.name }'`)
	if (route.handler==null) throw new Error(`Missing handler property in route '${ route.name }'`)

	// Check if path is relative
	if (path.isAbsolute(route.path)===true) throw new Error(`Path in route '${ route.name }' must be relative`)

	// Check if handler is a string or function
	if (typeof route.handler==='string')   route.handler = require(route.handler)
	if (typeof route.handler!=='function') throw new Error(`Handler in route '${ route.name }' is not a function nor a string`)

	// Provide fallbacks
	if (route.opts==null) route.opts = {}

	return route

}

/**
 * Parse and validate a path.
 * @public
 * @param {String} filePath - Path to a folder or file.
 * @returns {String} filePath - Validated and absolute path to a folder or file.
 */
const _path = function(filePath) {

	// Make filePath absolute
	filePath = path.resolve(filePath)

	return filePath

}

/**
 * Parse and validate options.
 * @public
 * @param {Object} opts - Additional optional options.
 * @returns {Object} opts - Validated additional optional options.
 */
const _opts = function(opts) {

	// Copy object to prevent changes by reverence
	opts = Object.assign({}, opts)

	// Set default value when an option is missing or has an incorrect type
	opts.ignore  = (Array.isArray(opts.ignore)===true ? opts.ignore : [])
	opts.polling = (opts.polling===true ? true : false)
	opts.verbose = (opts.verbose===true ? true : false)
	opts.open    = (opts.open===false ? false : true)

	return opts

}

/**
 * Parse and validate callbacks.
 * @public
 * @param {?Function} next - A callback that handles a response.
 * @returns {Function} next - A validated callback that handles a response and throws errors.
 */
const _next = function(next) {

	// Ensure that next is a function
	if (typeof next!=='function') next = (err) => {

		if (err!=null) throw err

	}

	return next

}

/**
 * @public
 */
module.exports = {
	route : _route,
	path  : _path,
	opts  : _opts,
	next  : _next
}