如果在对象内部找到值，则返回键

Question

有一个像这样的对象

var animals = { "dog": ["black", "red", "green"],
"cat": ["pink", "red", "white"],
"bird": ["green", "grey", "yellow"]};

我想返回具有特定颜色的动物的名称，例如，对于"red"，我想返回包含["dog", "cat"]的数组；尝试过这样做，但我只得到了Array(0(或Array(1(

function findColor(animals, color) {
var result = [];
if (Object.values(animals).indexOf(color) > -1) {
result.push(color);
}
return result;
}
console.log(findColor(animals, "red"));

Answer 1

您可以简单地使用Object.keys和filter

var animals = {
"dog": ["black", "red", "green"],
"cat": ["pink", "red", "white"],
"bird": ["green", "grey", "yellow"]
};
function findColor(animals, color) {
return Object.keys(animals).filter(key=>animals[key].includes(color))
}
console.log(findColor(animals, 'red'));

---

为什么我的代码不工作？

indexOf使用严格的比较，Object.values(动物(返回一个2d数组，您正试图将其与字符串值匹配，您需要在键上循环并在2d数组上的子数组上使用indexOf

var animals = {"dog": ["black", "red", "green"],"cat": ["pink", "red", "white"],"bird": ["green", "grey", "yellow"]};
function findColor(animals, color) {
var result = [];
Object.keys(animals).forEach(v => {
if (animals[v].indexOf(color) > -1) {
result.push(v)
}
})
return result;
}
console.log(findColor(animals, "red"));

Answer 2

您可以使用Object.keys，然后迭代数组，然后根据条件进行检查：

var animals = { "dog": ["black", "red", "green"],
"cat": ["pink", "red", "white"],
"bird": ["green", "grey", "yellow"]};
function findColor(animals, color) {
let result = []
Object.keys(animals).forEach(key=>{
if(animals[key].indexOf(color)>-1){
result.push(key)
}
});
return result;
}
console.log(findColor(animals, "red"));