如何计算数组中对象键的总和-javascript [英] How to calculate sum of object keys in array - javascript

问题描述

我正在使用Firebase并进行本地响应.

I am working with firebase and react native.

我从Firebase数据库返回了一个看起来像这样的数组.

I have returned an array from my firebase database that looks like this.

[Object, Object, Object]

在每个对象下，我都返回了一个单独的项目"level:4".

Under each object I have returned a single item, "level:4".

所以我有三个包含4,5,6的对象.如何将它们加在一起?

So I have three objects containing 4,5,6. How do I sum these together?

谢谢！

推荐答案

一个简单的循环

var a = [{level:1},{level:2},{level:3},{level:4}],
        total = 0;
    for (var i=0; i<a.length; i++) {
        total += a[i].level;
    }
console.log('total', total)

或减少

var a = [{level:1},{level:2},{level:3},{level:4}]
console.log(a.reduce( function(cnt,o){ return cnt + o.level; }, 0))

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