TypeScript and member that doesn't give the same value -

i'm developing simple application , have class, in need console.log result of function passed in parameters.

context

i m trying make simple di container based on ng2 1 (simpler, understand way of work) based on api.

so, have injector class, binding class , resolvedbinding class. injector accepts binding in parameters create resolvedbinding objects

here injector class :

import {resolvedbinding} "./resolvedbinding"; import {binding} "./binding";   export class injector {       private _binds:array<resolvedbinding>;       constructor(bindings:resolvedbinding[]) {         this._binds = bindings;     }      public static resolveandcreate(binds:array<binding>):injector {         return new injector(injector.resolve(binds));     }      get(token:any) {         (var in this._binds) {             if (this._binds[i].key === token) {                 return this._binds[i].factory();                 /*if(new this._binds[i].factory instanceof object)                   else                  return this._binds[i].factory();*/             }         }          return null;     }      static resolve(binds:array<binding>):array<resolvedbinding> {         var resolvedbindings = new array<resolvedbinding>();          (var  in binds) {             var factory;              if (binds[i].object.toclass) {                 factory = binds[i].object.toclass;             } else {                 if (binds[i].object.tofactory) {                     factory = binds[i].object.tofactory;                 }                 else {                     if (binds[i].object.tovalue) {                         factory = ()=> {                             return binds[i].object.tovalue;                         }                     }                     else {                         /* else ? */                     }                 }             }              resolvedbindings.push(new resolvedbinding(binds[i].token, factory));         }           return resolvedbindings;     } } 

here's binding class :

export class binding {      private _token:any;     private _object:any;      constructor(token, object) {         this._token = token;         this._object = object;     }      public token():any {         return this._token;     }      public object():any {         return this._object;     } } 

and resolvedbinding class :

export class resolvedbinding {      private _key:any;     private _factory:any;      constructor(key:any, factory:any) {         this._key = key;         this._factory = factory;         console.log(this._factory()); // gives result;     }      public key():any {         return this._key;     }      public set key(value:any) {         this._key = value;     }      public factory():any {         console.log(this._factory()); // gives undefined;         return this._factory;     }  } 

here's how call injector main class :

import { injector } './ioc/injector'; import { binding } './ioc/binding'; import { car } './ioc/car';  var injector = injector.resolveandcreate([     new binding(car, {toclass: car}),     new binding(string, {tovalue: "hello !"}),     new binding(number, {         tofactory: () => {             return 1 + 2;         }     }) ]);  var carc = injector.get(car); var mystring = injector.get(string); var mynumber = injector.get(number);   console.log(carc); // undefined console.log(mystring); // undefined console.log(mynumber); // 3 

problem

the problem seems when instantiate resolvedbinding class , push array. in fact, _factory property has value in constructor, when try log getter, gives me undefined, , undefined when trying car instance.

the for loop incorrectly captures loop variable here:

    if (binds[i].object.tovalue) {         factory = ()=> {             return binds[i].object.tovalue; // <-- bad!         }     } 

see javascript closure inside loops – simple practical example