javascript - Angular : loop over object data loaded from a webservice -

i'm loading data form external webservice. my code looks :

my service ( load restfull data):

import {injectable} '@angular/core'; import {http} '@angular/http'; import 'rxjs/add/operator/map';  @injectable() export class httpservice {   constructor(private http: http) {}    loaddataitems(url: string) {     return this.http.get(url)       .map(data => {         data.json();         return data.json();       });   } } 

my component (where injecting previous service display data):

import {component, oninit} '@angular/core'; import 'rxjs/add/operator/map' import {httpservice} '../http.service';  import * $ 'jquery'; import * highcharts 'highcharts';  @component({   selector: 'app-list',   templateurl: './list.component.html',   styleurls: ['./list.component.css'],   providers: [httpservice] })  export class listcomponent implements oninit {    dataitems: any;   nb = 0;   private dataurl = 'http://localhost:3000/list';  // url web api    constructor(private dataserver: httpservice ) {}   ngoninit() {     this.dataserver.loaddataitems(this.dataurl).subscribe(       data => {         this.dataitems = data;         console.log(this.dataitems);       }     );     (let = 0 ; < this.dataitems.length ; i++) {       if (this.dataitems.g = 'chrome') {         this.nb++       }     }      // build chart       highcharts.chart('chart2', {         chart: {           plotbackgroundcolor: null,           plotborderwidth: null,           plotshadow: false,           type: 'pie'         },         title: {           text: 'browser market shares january, 2015 may, 2015'         },         tooltip: {           pointformat: '{series.name}: <b>{point.percentage:.1f}%</b>'         },         plotoptions: {           pie: {             allowpointselect: true,             cursor: 'pointer',             datalabels: {               enabled: false             },             showinlegend: true           }         },         series: [{           name: 'brands',           colorbypoint: true,           data: [{             name: 'microsoft internet explorer',             y: 56.33           }, {             name: 'chrome',             y: 24.03,             sliced: true,             selected: true           }, {             name: 'firefox',             y: 10.38           }, {             name: 'safari',             y: 4.77           }, {             name: 'opera',             y: 0.91           }, {             name: 'proprietary or undetectable',             y: 0.2           }]         }]       });   } } 

my purpose loop of items of received object data , need count data specific attribute :

  if (this.dataitems.g = 'chrome')  

but got error indicating not defined :

this.dataitems.length

i won't filter ngfor , ngif , because wanna catch counted value in ts file , use in highchart widget composant .

any ideas ??

for count or filter can use filter... long time no see syntax may wrong...

       var query = myarray.filter(                        function(element){                           return element.propert == neededvalue &&                                   element.property == othervalue;                        }                    );         return query?query.length:0; 

good luck