JavaScript嵌套对象数组，如何循环遍历数组的 'KEY'？

Question

var myCollection = {
"cars": [
          { "name":"Ford", "models":[ "Fiesta", "Focus", "Mustang" ] },
          { "name":"BMW", "models":[ "320", "X3", "X5" ] },
          { "name":"Fiat", "models":[ "500", "Panda" ] }
        ]
}
for ( x in myCollection ) {
  document.getElementById("id1").innerHTML += x + "<br />";
}

答:汽车
同样，我如何显示数组内的 'KEY' 值，即 “姓名” 或 “模特”

for ( x in myCollection.cars ) {
  document.getElementById("id1").innerHTML += x + "<br />"; 
}

答:
0
1
2
为什么它返回数组索引值，如何显示 'KEY' 值 'name' 或 'models' ？

预期答案:

name      models 

name  OR  models 

name      models 

Answer 1

for 循环遍历每个索引，因此您必须获取该索引并深入到数组中

var myCollection = {
"cars": [
          { "name":"Ford", "models":[ "Fiesta", "Focus", "Mustang" ] },
          { "name":"BMW", "models":[ "320", "X3", "X5" ] },
          { "name":"Fiat", "models":[ "500", "Panda" ] }
        ]
}
for ( x in myCollection.cars ) {
  var keys = Object.keys(myCollection.cars[x])
  document.getElementById("id1").innerHTML += keys[0] + "<br />";
}

myCollection.cars[x] 是获取数组中特定对象的方法，并从 Object.keys() 中获取该对象的键。如果你想要值和键

for ( x in myCollection.cars ) {
  var keys = Object.keys(myCollection.cars[x])
  document.getElementById("id1").innerHTML += 
     keys[0] + " : " + myCollection.cars[x].name + " <br />" +
     keys[1] + " : " + myCollection.cars[x].models + "<hr />";
}