向现有 javascript 对象添加新属性答案

【问题标题】：Adding new property to existing javascript object向现有 javascript 对象添加新属性
【发布时间】：2018-07-24 08:17:49
【问题描述】：

我正在尝试向数组中的每个对象添加格式：“电影”，但我无法弄清楚。

var movie = [
    {title: "A Clockwork Orange", year: "1971", raiting: "8.3", genre: "Crime, Drama, Sci-Fi"},
    {title: "Full Metal Jacket", year: "1987", raiting: "8.3", genre: " Drama, War"},
    {title: "Pulp Fiction", year: "1994", raiting: "8.9", genre: "Crime, Drama"},
    {title: "Fight Club", year: "1999", raiting: "8.8", genre: "Drama"},
    {title: "Interstellar", year: "2014", raiting: "8.6", genre: "Adventure, Drama, Sci-Fi"}
];


movie.forEach(function () {
    movie.format = "film";
});


movie.forEach(function (element) {
    console.log(element);
});

【问题讨论】：

只是未来需要记住的一点，使用for ... in 或for ... of 循环可以让您在范围界定方面少很多麻烦。

标签： javascript arrays object foreach properties

【解决方案1】：

您需要将参数传递给function 并将新属性添加到其中

movie.forEach(function (element) {
    element.format = "film";
});

【讨论】：

【解决方案2】：

使用goes to 运算符。

var movie = [    {title: "A Clockwork Orange", year: "1971", raiting: "8.3", genre: "Crime, Drama, Sci-Fi"},    {title: "Full Metal Jacket", year: "1987", raiting: "8.3", genre: " Drama, War"},    {title: "Pulp Fiction", year: "1994", raiting: "8.9", genre: "Crime, Drama"},    {title: "Fight Club", year: "1999", raiting: "8.8", genre: "Drama"},    {title: "Interstellar", year: "2014", raiting: "8.6", genre: "Adventure, Drama, Sci-Fi"}];

let i = movie.length;
while (i --> 0) movie[i].format = 'film';
console.log(movie);

.as-console-wrapper {
  max-height: 100% !important
}

【讨论】：

【解决方案3】：

如果你也喜欢 ES6，你当然可以用粗箭头来做到这一点。

movie.forEach(element => element.format = "film");

【讨论】：