从对象数组中提取值

Question

I have an array that looks like this one:

[
    {
        "users": [
            {
               "name": "John",
               "location": "USA",
                "age": "34",
            },
           {
                "name": "John",
               "location": "California",
                "address": "Silk Road 123"
            },
           {
               "name": "Jane",
               "last-name": "Edmus"
               "location": "USA"
            }
        ]
    },

]

I want to merge the objects whose name match. I found this helper function:

 findByMatchingProperties = (set, properties) => {
  return set.filter(function (entry) {
      return Object.keys(properties).every(function (key) {
          return console.log(entry[key] === properties[key]);
      });
  });
}

But it is not budging. Any ideas on how I could go about this? The expected outcome should be:

 [ { "users": [ { "name": "John", "location": ["USA", "California"}, "age": "34", "address": "Silk Road 123" }, { "name": "Jane", "last-name": "Edmus" "location": "USA" } ] }, ] 

Answer 1

You can achive this by using Map object for optimization and then converting it back to array. Check out code below.

 const users = [ { "name": "John", "location": "USA", "age": "34" }, { "name": "John", "location": "California", "address": "Silk Road 123" }, { "name": "John", "location": "Foo", "bar": "baz" }, { "name": "Jane", "last-name": "Edmus", "location": "USA" } ]; const mergeObjectsExceptProps = (exceptProps, o1, o2) => Object.entries(o2).reduce((acc, [ k, v ]) => { if (exceptProps.includes(k)) { return acc } let propValueToSet if (acc.hasOwnProperty(k)) { propValueToSet = [ ...(Array.isArray(acc[k]) ? acc[k] : [ acc[k] ]), v ] } else { propValueToSet = v } return { ...acc, [k]: propValueToSet, } }, o1) const usersMap = new Map() for (const user of users) { const foundUser = usersMap.get(user.name) if (foundUser) { usersMap.set(user.name, mergeObjectsExceptProps([ 'name' ], foundUser, user)) } else { usersMap.set(user.name, user) } } const result = [ ...usersMap.values() ] console.log(result) 

Answer 2

You could reduce the users array and group them based on the name . Destructure each user and get the name and rest of the properties separately. Loop through the keys of rest and check if the key already exists in the nested value. If it exists, create an array of values. Else, just add the value:

 const input = [{users:[{name:"John",location:"USA",age:"34"},{name:"John",location:"California",address:"Silk Road 123"},{name:"Jane","last-name":"Edmus",location:"USA"}]}]; const merged = input[0].users.reduce((acc, o) => { const { name, ...rest } = o; const group = acc[name]; // check if name already exists in the accumulator if(group) { Object.keys(rest).forEach(key => { if(key in group) group[key] = [].concat(group[key], o[key]) else group[key] = o[key]; }) } else acc[name] = o; return acc; },{}) const users = Object.values(merged) console.log([{ users }]) 

This is what the merged object looks like:

{
  "John": {
    "name": "John",
    "location": ["USA", "California"],
    "age": "34",
    "address": "Silk Road 123"
  },
  "Jane": {
    ...
  }
}

Use Object.values() to get the values of this object to an array