获取匹配值的索引

Question

我已经在mongodb atlas中创建了在线集群，然后在monitch javascript编辑器中创建了mongodb Stitch应用程序，匹配时如何获取x的索引？例子：

{
"_id": 5646546,
"items":[   {"x": 12, "y": 4} ,  {"x": 12, "y": 4}   ]

}

因此，当x = 12时索引应为0

Answer 1

您可以像下面这样针脚地编写javascript函数：

const getIndex = (inputArray, match) => {
  return inputArray.findIndex(element => element.x == match);
};

let obj = {
  _id: 5646546,
  items: [
    { x: 12, y: 4 },
    { x: 12, y: 4 }
  ]
};

let obj2 = {
  _id: 5646547,
  items: [
    { x: 121, y: 4 },
    { x: 12, y: 4 },
    { x: 122, y: 4 }
  ]
};

console.log(getIndex(obj.items, 12)); // prints 0
console.log(getIndex(obj2.items, 122)); // prints 2