如果在对象中找到值，则返回键

Question

有一个对象，如：var animals = { "dog": ["black", "red", "green"],                 "cat": ["pink", "red", "white"],                 "bird": ["green", "grey", "yellow"]};我想取回具有某种颜色的动物的名称，例如"red"我想返回一个包含["dog", "cat"];的数组。尝试这样做，但我只返回 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'));

为什么我的代码不起作用？

indexOf 使用严格比较，Object.values(animals) 返回一个二维数组，并且您试图将其与字符串值匹配，您需要执行的操作是遍历键并在二维数组的子数组上使用 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"));