如果 for 循环找不到我想要的东西，就做一些事情

我有一个常见的问题，我想知道是否有人有比我到目前为止所做的更好的方法来解决它。

我想循环一个数组来查找一个对象并更新它。如果该对象不存在，我想将其附加到数组中。我通常处理更复杂的对象，这使得问题变得更加复杂。

var movies = [
    { _id: 1, title:"Movie 1" }, 
    { _id: 2, title: "Another Movie" }
];

var myTheater = { location:"here", current_movies: movies };

// A movie to check. The _id may or may not be in movies.
var aMovie = { _id: 3, title: "Something New" };

// boolean flag to let us know if something happened
var updated = false;

// look through all movies and my theater and update as needed
for(var i = 0, len = myTheater.current_movies.length; i<len; i++){
    if( myTheater.current_movies[i]._id === aMovie._id ){
        console.log("Updating movie name.");
        myTheater.current_movies[i].title = aMovie.title;
        updated = true;
        break;
    }
}

// check if anything was updated and add the movie if not
if(!updated){
    myTheater.current_movies.push(aMovie);
}

有没有更好的方法来做到这一点，或者使用标志是最好的选择？谢谢！

使用原生的Array.prototype.find https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find像这样：

var movies = [{ _id: 1, title:"Movie 1" }, { _id: 2, title: "Another Movie" }];
var myTheater = { location:"here", current_movies: movies };
var aMovie = { _id: 3, title: "Something New" };



// check if there is a movie with the same id as aMovie
var found = myTheater.current_movies.find(m => m._id == aMovie._id);

if(found) // if we found something
  found.title = aMovie.title; // update it's title
else
  /*things to do if nothing was found*/
  console.log("nothing found!");

箭头功能：

我传递给的函数（回调）find叫做箭头功能 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions。您可以致电find使用像这样的常规函数​​：

var found = myTheater.current_movies.find(function(m) {
    return m._id == aMovie._id;
});