JavaScript中如何在对象数组里通过if语句匹配field_id并返回对应值

Hey there! Let's figure out how to get that specific value you need. You've got an array of objects, and you want to pull the value where field_id is 40 (which is 111 in your example). Here are a few simple, common ways to do this in JavaScript:

Method 1: Use Array.prototype.find() (Recommended) #

This is the cleanest and most efficient approach because find() stops traversing the array as soon as it finds the first matching item.

const 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 }
];

// Find the first object where field_id is 40
const matchingItem = myObj.find(item => item.field_id === 40);

// Safely get the value (in case no match is found)
const targetValue = matchingItem ? matchingItem.value : undefined;

console.log(targetValue); // Output: 111

We add a check for matchingItem to avoid errors if there's no object with field_id: 40 in the array.

Method 2: Use a forEach Loop #

If you need to do extra processing while traversing the array, a forEach loop works well:

const 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 }
];

let targetValue;

myObj.forEach(item => {
  if (item.field_id === 40) {
    targetValue = item.value;
    // Skip remaining iterations once we find the match
    return;
  }
});

console.log(targetValue); // Output: 111

Method 3: Use Array.prototype.filter() #

This is useful if you might have multiple objects with field_id: 40—it returns all matching items in an array:

const 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 }
];

// Get all objects where field_id is 40
const matchingItems = myObj.filter(item => item.field_id === 40);

// If there's at least one match, grab the first item's value
const targetValue = matchingItems.length > 0 ? matchingItems[0].value : undefined;

console.log(targetValue); // Output: 111

Quick Note #

Unless you expect multiple matching objects, find() is the best choice—it's faster and more concise for single-match scenarios.

内容的提问来源于stack exchange，提问作者Lizz Parody