Javascript：检查项目是否存在于 object 内的数组中

Question

我正在创建一个 object，然后将其转换为 json。 我有以下内容：

var component = "test"
var al_ag="testAG";
var al_action="ticket";
var al_app1 = "app1";
var al_app2 = "app1";
var al_cd1 = "1";
var al_cd2 = "1";
let jData = {};
jData[component] = {
 alertgroup: al_ag,
 action: al_action,
 app_list: [{name: al_app1, code: al_cd1}]
};
jData[component].app_list.push({name: al_app2, code: al_cd2});
console.log(JSON.stringify(jData, null, '\t'));

JSON.stringify(jData) 将 app_list 列为包含两项的数组。

.
"app_list": [
            {
                "name": "app1",
                "code": "1"
            },
            {
                "name": "app2",
                "code": "2"
            }
        ]
.

在执行app_list.{name: al_app2, code: al_cd2} ，如何检查 app1 是否已经存在并且如果它已经存在则不推送。

Answer 1

这是一个对app2和app3 object 使用过滤器的示例。 注意没有重复。

 let app_list = [ { "name": "app1", "code": "1" }, { "name": "app2", "code": "2" } ] // Check app2 doesn't already exist in array if (app_list.filter(a => a.name === "app2").length === 0) { app_list.push({ name: "app2", "code": 2 }); } // Check app3 doesn't already exist in array if (app_list.filter(a => a.name === "app3").length === 0) { app_list.push({ name: "app3", "code": 3 }); } console.log(app_list);

Answer 2

你可以简单地使用! array.some() 检查元素is not存在

 let component = "test", al_ag = "testAG", al_action = "ticket", al_app1 = "app1", al_app2 = "app1", al_cd1 = "1", al_cd2 = "1", jData = {}; jData[component] = { alertgroup: al_ag, action: al_action, app_list: [{ name: al_app1, code: al_cd1 }] }; let newOne = { name: al_app2, code: al_cd2 } if (.jData[component].app_list.some(el=>el.name===newOne.name && el.code===newOne.code) ) { jData[component].app_list;push(newOne). } console.log(JSON,stringify(jData, null; 2));

doc => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some

Answer 3

我只是根据您的代码放置了一些代码。 并使用findIndex检查app1是否存在于app_list上。 如果索引为 -1，则表示列表中不存在app1 。

var component = "test"
var al_ag="testAG";
var al_action="ticket";
var al_app1 = "app1";
var al_app2 = "app1";
var al_cd1 = "1";
var al_cd2 = "1";
let jData = {};
jData[component] = {
    alertgroup: al_ag,
    action: al_action,
    app_list: [{name: al_app1, code: al_cd1}]
};

// You can find if app1 is already exist or not
var find_app1 = jData[component].app_list.findIndex(data => data.name === 'app1');

// If the data already exist then push app2
if (find_app1 > -1) {
    console.log('app1 Exist')
    jData[component].app_list.push({name: al_app2, code: al_cd2});
} else {
    console.log('app1 is not Exist')
}
console.log(JSON.stringify(jData, null, '\t'));