如何在 JS 的字典中添加新元素？

Question

我有这种字典：INPUT

movies = {
        'big' : {
            actors : ['Elizabeth Perkins', 'Robert Loggia']
        },
        'forrest gump' : {
            actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise']
        },
        'cast away' : {
            actors : ['Helen Hunt', 'Paul Sanchez']
        }
    };

我想用这本字典来换一本。 例如，我必须创建一个名为“moviesWithActors”的函数，它将接收两个参数：“movies”和“actor”。 演员可能是“汤姆汉克斯”，所以当你发现他在电影中时，你不添加到嵌套数组中，但如果不是，你添加。

输出

movies = {
        'big' : {
            actors : ['Elizabeth Perkins', 'Robert Loggia', 'Tom Hanks']
        },
        'forrest gump' : {
            actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise']
        },
        'cast away' : {
            actors : ['Helen Hunt', 'Paul Sanchez', 'Tom Hanks]
        }
    };

我这样做：

for (const value of Object.values(newMovies)){
    console.log(value.actors)
    for (const act of value.actors){
        //console.log(act)
        if (act == actor) {
            console.log("Ok, not add")
        }else{
            console.log("Here I have to add");
        }
    }
}

其中“newMovies”是“movies”和“actor =“Tom Hanks”的副本，但我无法添加到actors中的数组：[ ... ]。有什么建议吗？我可以使用map()吗？

Answer 1

根据我所理解的要求，存在一个现有的电影对象数组，并且您想在这些电影中分配一个hero 。 我们必须忽略传递的英雄名称是否已经存在于该电影中，否则在该电影下添加该英雄。 如果我的理解是正确的，你去：

 const movies = { 'big' : { actors : ['Elizabeth Perkins', 'Robert Loggia'] }, 'forrest gump' : { actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise'] }, 'cast away' : { actors : ['Helen Hunt', 'Paul Sanchez'] } }; function updateMoviesList(obj, heroName) { Object.keys(obj).forEach(key => { if (!obj[key].actors.includes(heroName)) { obj[key].actors.push(heroName) } }) return obj; } console.log(updateMoviesList(movies, 'Tom Hanks'));

Answer 2

您可以使用 Push()

像这样来自文档

let sports = ['soccer', 'baseball']
let total = sports.push('football', 'swimming')

console.log(sports)  // ['soccer', 'baseball', 'football', 'swimming']
console.log(total.length)   // 4

要访问字典中的数组，您必须首先访问它

movies['big']['actors'].push('New Actor')

为了不被“硬编码”，如果你这样做？

let actor = 'Tom Hanks'
for (const value of Object.values(newMovies)){
    for (const act of value.actors){
        if (value.actors.includes(actor)) { //Here you check if actor contains in array
            console.log("Ok, not add")
        }else{
            console.log("Here I have to add");
            value.actors.push(actor) //if not push to array          
            }
        }
    }

Answer 3

I was suggested to use map instead and the class Object...

 function actorInMovies(movies, actor) { let mappedObject = { ...movies}; Object.entries(movies).map(movie => { const movieName = movie[0]; const actors = movie[1].actors; if (!actors.includes(actor)) actors.push(actor); mappedObject = { ...mappedObject, [movieName]: { actors } }; }); return mappedObject } function main(){ const movies = { 'big' : { actors : ['Elizabeth Perkins', 'Robert Loggia'] }, 'forrest gump' : { actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise'] }, 'cast away' : { actors : ['Helen Hunt', 'Paul Sanchez'] } }; const actor = 'Tom Hanks'; console.log(actorInMovies(movies, actor)) } main();