Structs

struct.js

var structure = (function () {
  "use strict";
  function BaseStruct(values) {
    for(var i= values.length-1; i>= 0; i--) {
      this[i] = values[i]
    }
  }
  BaseStruct.prototype.toJSON = function toJSON() {
    var array = new Array(this.length)
    for(var i = array.length-1; i >= 0; i--) {
      array[i] = this[i]
    }
    return array
  }
  return function structure(properties, methods) {
    function Struct(values) {
      if(!(this instanceof Struct)) {
        return new Struct(values)
      }
      BaseStruct.call(this, values)
    }
    Struct.prototype = Object.create(BaseStruct.prototype, {
      length:{ get() {
        return properties.length
      }}
    })
    if(typeof methods === 'object') {
      Object.keys(methods).forEach(method => {
        var descriptor = Object.getOwnPropertyDescriptor(methods, method)
        Object.defineProperty(Struct.prototype, method, descriptor)
      })
    }
    properties.forEach((property, index) => {
      Object.defineProperty(Struct.prototype, index, {
        enumerable: false,
        configurable: true,
        get() {
          return this[property]
        },
        set(value) {
          return this[property] = value
        }
      })
    })
    return Struct
  }
}())


var Person = structure(['name', 'age'])

var person = Person(['Per', 19])


var CSV = {
  parse(string, Value) {
    var lines = string.split('\n')
    if(typeof Value !== 'function') {
      Value = structure(lines.shift().split(','), Value)
    }
    return lines.map(line => Value(line.split(',')))
  },
  stringify(array) {
    var properties = Object.keys(array[0])
    var result = [ properties.join(',') ]
    for(var item of array) {
      result.push(properties.map(property => item[property]).join(','))
    }
    return result.join('\n')
  }
}

CSV.parse(CSV.stringify([person, person]), Person)
   .every(person => person instanceof Person)