如何将一组对象合并到一个数组中，然后过滤掉重复项

Question

Firstly, I am trying to merge an array of many objects into a single array with every key in each object.

Lastly, any duplicate items in the array should be removed as well as any elements named "name".

Input:

const data = [
  {
    name: '10/20',
    Tyler: 1,
    Sonia: 0,
    Pedro: 0,
  },
  {
    name: '10/23',
    Tyler: 0.5,
    Sonia: 0.25,
    Pedro: 0.75,
    George: 0.5,
  },
];

Output:

["Tyler", "Sonia", "Pedro", "George"]

This is what I've tried so far:

const mergedData = data.reduce((prev, cur) => {
  const obj = cur[0];
  const keys = Object.keys(obj);
  const names = keys.splice(1);
  return { names };
}, []);

I am trying to capture any key name other than "name" and add it to the final array. However, this is where I get stuck because I get this error, TypeError: Cannot convert undefined or null to object

Note: Objects may be different lengths, contain a mix of names, but never any duplicates.

Answer 1

An option is to find all keys put in a set and remove the name key

 const data = [ { name: '10/20', Tyler: 1, Sonia: 0, Pedro: 0, }, { name: '10/23', Tyler: 0.5, Sonia: 0.25, Pedro: 0.75, George: 0.5, }, ]; const set = new Set(data.reduce((acc, i) => [...acc, ...Object.keys(i)], [])); set.delete('name'); const result = [...set]; console.log(result);

Answer 2

 const data = [ { name: '10/20', Tyler: 1, Sonia: 0, Pedro: 0, }, { name: '10/23', Tyler: 0.5, Sonia: 0.25, Pedro: 0.75, George: 0.5, }, ]; const result =Array.from(new Set(data.reduce((acc, i) => [...acc, ...Object.keys(i)], []))); console.log(result)

Answer 3

If you have access to ES6 methods, you can do this using a Set (unique values are ensured at creation) and converting it back into an array if you want through Destructuring .

 data = [{name: '0', Tyler: '1', Dan: '2', Carl: '3'}, {name: '0', Tyler: '1', Dan: '2', Eric: '3', Danny: '4'}]; const output = (data) => { let output = []; // This makes sure you get each array and then strips just the keys as desired data.forEach(item => { output = output. concat(Object.keys(item)) }); // This creates the set, strips our dups, and then spreads itself into an array return [...new Set(output)] // Strip out the 'name' key as needed // NOTE: This should be a param instead of hard-coded, but this is easier to show .filter(res => res != 'name'); } console.log(output(data));

This should be fairly performant considering it only navigates the full array one time and each object itself shouldn't have millions of properties to cause .keys() any issues.