如果在JavaScript中的对象中声明

Question

我有这个对象，我想在field_id等于40时返回一个值。我该怎么做？在这种情况下，我想返回111

  myObj = [{
   id: 11,
   company_id: 1,
   field_id: 7,
   value: 700,
},
  {
   id: 12,
   company_id: 1,
   field_id: 40,
   value: 111,
},
  {
   id: 13,
   company_id: 1,
   field_id: 41,
   value: 222,
 }]

Answer 1

for(item of myObj) { if(item.field_id == 40) return item.value; }

Answer 2

// Array with objects
myArr = [{
    id: 11,
    company_id: 1,
    field_id: 7,
    value: 700,
  },
  {
    id: 12,
    company_id: 1,
    field_id: 40,
    value: 111,
  },
  {
    id: 13,
    company_id: 1,
    field_id: 41,
    value: 222,
  }
];

myFilter = (arr, key, value, output) => arr.filter(o => o[key] === value).map(r => r[output]);

// Result is an array (if several solutions)
console.log(myFilter(myArr, "field_id", 40, "value"));

Answer 3

你需要循环遍历数组

var i;
for (i = 0; i < myObj.length; i++) { 
    if (myObj[i].field_id == 40) {
        return myObj[i].value
     }
}