问离子2类型脚本变量始终返回未定义

EN

function1(){
let currentPage;
let nextPage;
let _this =this;
this.storage.get('current_page').then((val) => {
  currentPage = val;
  nextPage = currentPage + 1;
_this.function2(nextPage);
});
}

function2(nextPage){
let leadsArray;
return new Promise(resolve => {
  this.http.get(this.webServiceUrl+'Inquiries/bwwFhAppTestApi3/'+this.clientId+'/'+nextPage)
    .map(res => res.json())
    .subscribe(data => {
      //console.log(data);
      leadsArray = data.leads;
      this.storage.set('current_page', nextPage);
      resolve(leadsArray);
    });
});
}

doInfinite(infiniteScroll) {
  let currentPage;
  let nextPage;
  this.storage.get('current_page').then((val) => {
    currentPage = val;
    nextPage = currentPage + 1;

    this.webService.getOpenLeadsByPage(nextPage).then((result) => {
        for( var lead in result) {
            this.leads.push(result[lead]);
        }
        infiniteScroll.complete();
    });

  });
}