Filter only unique values from an array of object javascript

Question

I have an array of objects i want to filter only the unique style and is not repeated .

const arrayOfObj = [ {name:'a' , style:'p'} , {name:'b' , style:'q'} , {name:'c' , style:'q'}]

result expected : [ {name:'a' , style:'p'}]

Answer 1

Here is a solution in O(n) time complexity. You can iterate all entries to track how often an entry occurs. And then use the filter() function to filter the ones that occur only once.

const arrayOfObj = [
  { name: "a", style: "p" },
  { name: "b", style: "q" },
  { name: "c", style: "q" },
]

const styleCount = {}

arrayOfObj.forEach((obj) => {
  styleCount[obj.style] = (styleCount[obj.style] || 0) + 1
})

const res = arrayOfObj.filter((obj) => styleCount[obj.style] === 1)

console.log(res)