Warning: file_get_contents(/data/phpspider/zhask/data//catemap/8/meteor/3.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
Javascript Meteor.js:获取集合字段的总和_Javascript_Meteor - Fatal编程技术网

Javascript Meteor.js:获取集合字段的总和

Javascript Meteor.js:获取集合字段的总和,javascript,meteor,Javascript,Meteor,我收集了以下物品: Object_id: "CoQayo8QmhEJduwtr" category: "Computers" createdAt: Sat May 23 2015 17:53:30 GMT-0400 (EDT)link: "https://www.apple.com/mac-pro/" price: "4999.00" title: "Mac Pro" updatedAt: Sun May 24 2015 01:27:06 GMT-0400 (EDT) userId: "yN36

我收集了以下物品:

Object_id: "CoQayo8QmhEJduwtr"
category: "Computers"
createdAt: Sat May 23 2015 17:53:30 GMT-0400 (EDT)link: "https://www.apple.com/mac-pro/"
price: "4999.00"
title: "Mac Pro"
updatedAt: Sun May 24 2015 01:27:06 GMT-0400 (EDT)
userId: "yN36TFg742wZcyjQG"

我在页面上为每个用户显示了一个项目列表。如何为当前用户显示价格字段的总和?

您可以使用模板帮助程序,并结合使用多个下划线函数:

Template.user.helpers({
  // declare a new helper on your user page template
  priceSum: function(){
    // fetch every items belonging to the currently displayed user
    var userItems = Items.find({
      userId: this._id
    }).fetch();
    // extract the price property in an array
    var userItemsPrices = _.pluck(userItems, "price");
    // compute the sum using a simple array reduction
    return _.reduce(userItemsPrices, function(sum, price){
      return sum + parseFloat(price);
    }, 0);
  }
});

谢谢,这几乎可以工作,但我想,因为我将字段存储为字符串,所以它只是将值串联起来。将值转换为数字的最佳方法是什么?我已编辑代码,对当前迭代的价格使用
parseFloat
,以便将其转换为
数字。