如何计算已读为真的列表长度 [英] How to count length of list having read as true

问题描述

我有一个列表

let chats: Chats[] = [
{id: 1, name: "James Anderson",read=false},
{id: 2, name: "James Anderson",read=true},
{id: 3, name: "James Anderson",read=true},
{id: 4, name: "James Anderson",read=true},
]

在 cshtml 页面上，我曾经以 {{chats.length}} 为正确返回所有计数，但我需要返回读取值设置为 false 的计数

and on cshtml page I used to right as {{chats.length}} which return all the count but I need to return the count whose read value is set as false

即我需要计数为 1 而不是 4

i.e I need the count as 1 instead of 4

推荐答案

可以使用array.filter和length如下，

You can use array.filter and length as follows,

let result  = chats.filter(t=>!t.read).length;

演示

var chats = [
{id: 1, name: "James Anderson",read:false},
{id: 2, name: "James Anderson",read:true},
{id: 3, name: "James Anderson",read:true},
{id: 4, name: "James Anderson",read:true}
];

let result = chats.filter(t=>!t.read).length;
console.log(result);

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