如何通过嵌套在对象数组的属性中的对象属性的值在对象数组中找到多个索引？

Question

我有一个对象数组，每个对象都有一个“监视”属性，它本身就是一个对象数组。

let arr = 
        [ 
            {   
                id: 1, 
                name: "A", 
                watched: [ 
                            {movieId: 7, movieName: "Avatar"} , 
                            {movieId: 8, movieName: "Titanic"}
                        ]
            },
            {   
                id: 2, 
                name: "B", 
                watched: [   
                            {movieId: 1, movieName: "Armageddon"} , 
                            {movieId: 8, movieName: "Titanic"}
                        ]
            },
            {   
                id: 3, 
                name: "C", 
                watched: [   
                            {movieId: 1, movieName: "Armageddon"} , 
                            {movieId: 7, movieName: "Avatar"}
                        ]
            }

        ]

我需要根据给定的 MovieId 的索引数组。 如果我想要一个观看电影的索引数组，没有。 7（阿凡达） - 我会得到：

让 AvatarWatchers = [0,2]

我试过：

AvatarWatchers = arr.filter((item) => item.watched.find(movieObj => movieObj.movieId == 7) > -1 )

但它不起作用，我得到了一个空数组。

Answer 1

 let arr = [ { id: 1, name: "A", watched: [ {movieId: 7, movieName: "Avatar"} , {movieId: 8, movieName: "Titanic"} ] }, { id: 2, name: "B", watched: [ {movieId: 1, movieName: "Armageddon"} , {movieId: 8, movieName: "Titanic"} ] }, { id: 3, name: "C", watched: [ {movieId: 1, movieName: "Armageddon"} , {movieId: 7, movieName: "Avatar"} ] } ]; let result = arr.map((item, index) => ({...item, index})) .filter(item => item.watched.find(watchedItem => watchedItem.movieName === 'Avatar')) .map(item => item.index); console.log('expected result', result);