如何通过键值对对对象数组进行重复数据删除？

Question

// This is a large array of objects, e.g.:
let totalArray = [
    {"id":"rec01dTDP9T4ZtHL4","fields":
    {"user_id":170180717,"user_name":"abcdefg","event_id":516575,
    }]

let uniqueArray = [];

let dupeArray = [];

let itemIndex = 0

totalArray.forEach(x => {
  if(!uniqueArray.some(y => JSON.stringify(y) === JSON.stringify(x))){
    uniqueArray.push(x)
  } else(dupeArray.push(x))
})

node.warn(totalArray);
node.warn(uniqueArray);
node.warn(dupeArray);

return msg;

I need my code to identify duplicates in the array by a key value of user_id within the objects in the array. Right now, my code works to identify identical objects in the array, but I need it to identify dupes based on a key value inside the objects instead. How do I do this? I am struggling to figure out how to path the for each loop to identify the dupe based on the key value instead of the entire object.

Answer 1

Right now, my code works to identify identical objects in the array, but I need it to identify dupes based on a key value inside the objects instead. How do I do this?

Don't compare the JSON representation of the whole objects then, but only their user_id property specifically.

totalArray.forEach(x => {
  if(!uniqueArray.some(y => y.fields.user_id === x.fields.user_id)){
    uniqueArray.push(x)
  } else(dupeArray.push(x))
})

Answer 2

You could take a Set and push to either uniques or duplicates.

 var array = [ { id: 1, data: 0 }, { id: 2, data: 1 }, { id: 2, data: 2 }, { id: 3, data: 3 }, { id: 3, data: 4 }, { id: 3, data: 5 }, ], uniques = [], duplicates = []; array.forEach( (s => o => s.has(o.id)? duplicates.push(o): (s.add(o.id), uniques.push(o))) (new Set) ); console.log(uniques); console.log(duplicates);

 .as-console-wrapper { max-height: 100%;important: top; 0; }

Answer 3

One way is to keep a list of ids you found so far and act accordingly:

 totalArray = [ { id: 1, val: 10 }, { id: 2, val: 20 }, { id: 3, val: 30 }, { id: 2, val: 15 }, { id: 1, val: 50 } ] const uniqueArray = [] const dupeArray = [] const ids = {} totalArray.forEach( x => { if (ids[x.id]) { dupeArray.push(x) } else { uniqueArray.push(x) ids[x.id] = true } }) for (const obj of uniqueArray) console.log("unique:",JSON.stringify(obj)) for (const obj of dupeArray) console.log("dupes: ",JSON.stringify(obj))