js数组做合计，相同key（number类型）相加

需求介绍：从数组中把所有number类型根据相同key相加组成新的对象，其他的删掉！

let arr = [{
  name: "张三",
  num1: 100,
  num2: 100,
  state: 'true'
}, {
  name: "李四",
  num1: 100,
  num2: 100,
  state: 'true'
}, {
  name: "马武",
  num1: 100,
  num2: 100,
  num3: 200,
  state: 'false'
}, {
  name: "老娄",
  num1: 100,
  num2: 100,
  num3: 130,
  state: 'true'
}]

let obj = {};

arr.forEach(item => {
  for(let key in item) {
	if(typeof item[key] === 'number'){
	  let value = item[key];
  	  key in obj ? (obj[key] += value) : (obj[key] = value)
	}
  }
})

console.log('obj',obj)
//obj {num1: 400, num2: 400, num3: 330}