javascript - 从对象数组中，返回新数组中的键

Question

我有一个对象数组，必须在新数组中返回键 puppies: 此函数采用以下格式的狗数组:

[
  {breed: 'Labrador', puppies: ['Fluffy', 'Doggo', 'Floof'] },
  {breed: 'Rottweiler', puppies: ['Biscuits', 'Mary'] }
]

它应该返回所有狗的所有小狗的数组:

['Fluffy', 'Doggo', 'Floof', 'Biscuits', 'Mary']

到目前为止，这是我的代码:

function collectPuppies (dogs) {

    let solution=[];
    for(let i=0; i<dogs.length; i++){
      solution.push(dogs[i].puppies);
    }
    return solution;
  }

它将名称添加到解决方案中，但在 [[ ]] 之间返回它们:

Expected [ [ 'Spot', 'Spotless' ] ] to deeply equal [ 'Spot', 'Spotless' ]

我在 this 中看到了我的解决方案线程，所以我相信我并不太远，但无法弄清楚我做错了什么。谁能帮我吗？提前致谢。

Answer 1

使用 spread syntax将项目插入数组:

const dogs = [{"breed":"Labrador","puppies":["Fluffy","Doggo","Floof"]},{"breed":"Rottweiler","puppies":["Biscuits","Mary"]}];

function collectPuppies(dogs) {
  const solution = [];
  
  for (let i = 0; i < dogs.length; i++) {
    solution.push(...dogs[i].puppies);
  }
  
  return solution;
}

console.log(collectPuppies(dogs));

另一种选择是用 Array.map() 得到小狗。 , 并通过扩展到 Array.concat() 来压平结果:

const dogs = [{"breed":"Labrador","puppies":["Fluffy","Doggo","Floof"]},{"breed":"Rottweiler","puppies":["Biscuits","Mary"]}];

const collectPuppies = (dogs) => [].concat(...dogs.map(({ puppies }) => puppies));

console.log(collectPuppies(dogs));