remove duplicates from list typescript code example

Example 1: javascript remove duplicate in arrays

// 1. filter()
function removeDuplicates(array) {
  return array.filter((a, b) => array.indexOf(a) === b)
};
// 2. forEach()
function removeDuplicates(array) {
  let x = {};
  array.forEach(function(i) {
    if(!x[i]) {
      x[i] = true
    }
  })
  return Object.keys(x)
};
// 3. Set
function removeDuplicates(array) {
  array.splice(0, array.length, ...(new Set(array)))
};
// 4. map()
function removeDuplicates(array) {
  let a = []
  array.map(x => 
    if(!a.includes(x) {
      a.push(x)
    })
  return a
};
/THIS SITE/ "https://dev.to/mshin1995/back-to-basics-removing-duplicates-from-an-array-55he#comments"

Example 2: filter duplicate value in typescript

var arrOfObj = [
  {
    id:1 ,name:'abc',age:27
  },
  {
    id:2 ,name:'pqr',age:27
  },
  {
    id:1 ,name:'abc',age:27
  },
 ]

var setObj = new Set(); // create key value pair from array of array

var result = arrOfObj.reduce((acc,item)=>{
  if(!setObj.has(item.age)){
    setObj.add(item.age)
    acc.push(item)
  }
  return acc;
},[]);//converting back to array from mapobject

console.log(result);

Example 3: deduplicate array javascript

function uniq(a) {
   return Array.from(new Set(a));
}