oop - JavaScript: Assign values of arguments object as fields in an Object -

i converting object constructor form of

function obj(arg1, arg2, arg3, arg4, ..., argn-1, argn) {   this.name = arg1;   this.field = arg2;   this.etc = arg3;   ... } //obj 

to form of

function obj() {   var args = array.prototype.slice.call(arguments);    var defaultargs = {       'field'  :  default       ...   };   ... check args, etc   } //obj 

here code far:

function dsobj () {   var args = array.prototype.slice.call(arguments);    var defaultargs = {   'fields' : values or functions returning values   ...   };    var options = {};    (var in defaultargs) {      if (typeof(args[i] == 'undefined')) {        options[i] = defaultargs[i];      } else {        options[i] = args[i];      } //check if user supplied argument   } //for each possible argument    (var name in options) {     this.name = options[name]; //trying make fields - wrong   } //for each final parameter } //constructor dsobj 

so, need last part of above constructor. started programming javascript around week ago, , education goes far reading beginners syntax book. so, if there better way other stupid , direct way, please let me know. reason can't reference options array above of methods written object in way use "this.method" paradigm. please. guise. help.

i think need bracket notation instead of dot one:

for (var name in options) {     this[name] = options[name]; } 

be aware for...in loops iterate inherited properties, may want check options.hasownproperty(name) avoid that.

also note when iterate defaultargs, i each property. args indexed numbers, not custom keys.

you can use like

function dsobj () {   var argnames = ['fields', /*...*/],       defaultargs = [ /* ..., ... */];   (var i=0, l=arguments.length; i<l; ++i) {       this[argnames[i]] = arguments[i] || defaultargs[i];   } } 

or if arguments[i] can falsy, then

this[argnames[i]] = arguments[i] !== void 0 ? arguments[i] : defaultargs[i];