Javascript/React - 获取数组中匹配特定条件的第一项

Question

我有一个数组，比如说

[
    {
        lesson: 1,
        title: "Welcome",
        slug: "welcome",
        active: active,
        breakDay: false,
        started_time: new Date(),
        finished_time: null,
        completed: true,
        sublesson: [
            {
                lesson: 1.1,
                title: "Evaluation",
                slug: 'evaluation',
                completed: false,
                answers: []
            }
        ],
        answers: []
    },
    {
        lesson: 2,
        title: "Example",
        slug: "example",
        active: active,
        breakDay: false,
        started_time: null,
        finished_time: null,
        completed: false,
        sublesson: [
            {
                lesson: 2.1,
                title: "example2,
                slug: 'example2,
                answers: []
            }
        ],
        answers: []
    }
]

我需要找到一种方法来绘制第一个项目以达到特定条件。

我在我的 React 应用程序中尝试过，但很快意识到它实际上是在检查第一个项目而不是整个数组的这些条件是否为真。

    {
        lessons !== null ?

            lessons.map((item, index, arr) => (
                index === 0 && item.active === true ?
                <>
                <p>{item.title}</p>
                </>
                :
                null
            ))
            :
            null

    }

本质上，如何过滤第一个项目以满足特定条件，例如 item.active === true && item.completed === false ？

Answer 1

您可能需要此处的过滤器:

var data=[ { lesson: 1, title: "Welcome", slug: "welcome", active: 'active', breakDay: false, started_time: new Date(), finished_time: null, completed: true, sublesson: [ { lesson: 1.1, title: "Evaluation", slug: 'evaluation', completed: false, answers: [] } ], answers: [] }, { lesson: 2, title: "Example", slug: "example", active: 'active', breakDay: false, started_time: null, finished_time: null, completed: false, sublesson: [ { lesson: 2.1, title: "example2", slug: 'example2', answers: [] } ], answers: [] }];

var result = data.filter(({active, completed})=> active && !completed);

console.log(result);

或者find来获取第一个匹配的对象:

var data=[ { lesson: 1, title: "Welcome", slug: "welcome", active: 'active', breakDay: false, started_time: new Date(), finished_time: null, completed: true, sublesson: [ { lesson: 1.1, title: "Evaluation", slug: 'evaluation', completed: false, answers: [] } ], answers: [] }, { lesson: 2, title: "Example", slug: "example", active: 'active', breakDay: false, started_time: null, finished_time: null, completed: false, sublesson: [ { lesson: 2.1, title: "example2", slug: 'example2', answers: [] } ], answers: [] }];

var result = data.find(({active, completed})=> active && !completed);

console.log(result);