ForEach内部的ForEach Javascript

嗨,我如何循环槽阵列我已经循环槽?所以我把每个子阵列都换成了原来的阵列

array =  [
{
"DocNum": 210446, 
"DocType": "Test",
"DocumentLines": [
{
"LineNum": 0,
"ItemCode": "427"
}, 
{
"LineNum": 0,
"ItemCode": "34"
}
]
},
{
"DocNum": 210446, 
"DocType": "Test",
 "DocumentLines": [
{
  "LineNum": 0,
  "ItemCode": "427"
  }, 
  {
    "LineNum": 0,
    "ItemCode": "34"
    }
  ]
  }
 ]

for (let element of array) {
 newArray.push({
    key1: element.DocNum,
    key2: element.DocType,
    key3: element.DocumentLines[???].ItemCode
})}

所以阵列最终会是这样的

{ "key1":210446, "key2":Test, "key3": [{ItemCode: 34},{"ItemCode": 427}] }