如何使用Lodash比较两个对象并返回指定结构的新对象？

Alright, let's tackle this problem where we need to find entries in object1 whose names exist in object2, then extract specific fields to build our desired object3. Here's a clean, efficient approach using JavaScript:

Step-by-Step Implementation #

First, let's define our input objects clearly:

const object1 = { 
  "body": { 
    "items": [ 
      { 
        "data": { "name": "Smith", "status": "Ready", "userinfo": [ { "dob": "01/01/2000", "nickname": "Joe" } ] }, 
        "workinfo": { "company": "mycompany", "address": "101 Main str." } 
      }, 
      { 
        "data": { "name": "Luke", "status": "Ready", "userinfo": [ { "dob": "01/01/2001", "nickname": "LL" } ] }, 
        "workinfo": { "company": "mycompany", "address": "101 Main str." } 
      } 
    ] 
  } 
};

const object2 = { 
  "items": [ 
    { "name": "Smith", "status": "Ready" }, 
    { "name": "Luke", "status": "Ready" } 
  ] 
};

Basic Matching (Name Only) #

If we just need to match by name and extract name + status from object1:

// Create a Set of valid names from object2 for fast lookup
const validNames = new Set(object2.items.map(item => item.name));

// Filter and transform the data from object1
const object3 = object1.body.items
  .filter(item => validNames.has(item.data.name))
  .map(item => ({
    name: item.data.name,
    status: item.data.status
  }));

console.log(object3);
// Output:
// [ { name: 'Smith', status: 'Ready' }, { name: 'Luke', status: 'Ready' } ]

Enhanced Matching (Name + Status) #

If you need to ensure both name and status match between the two objects:

// Create a Map to link names to their expected status from object2
const userStatusMap = new Map(object2.items.map(item => [item.name, item.status]));

const object3 = object1.body.items
  .filter(item => {
    const expectedStatus = userStatusMap.get(item.data.name);
    // Check if the name exists AND status matches
    return expectedStatus && expectedStatus === item.data.status;
  })
  .map(item => ({
    name: item.data.name,
    status: item.data.status
  }));

Key Explanations #

• Set for Fast Lookup: Using a Set (or Map for enhanced matching) makes checking if a name exists much faster than looping through object2.items every time—critical if you're working with large datasets.
• Filter + Map: The combination of filter (to keep only matching entries) and map (to reshape the data into our desired format) is a concise, readable way to process the array.

内容的提问来源于stack exchange，提问作者John Glabb