배열에서 유일한 값만 추리기 (Get only unique values ​​in an array)

배열에서 유일한 값만 추리기 (Get only unique values ​​in an array)

기본 알고리즘

const source = [1, 2, 3, 2, 4, 5, 3, 3, 7];

for (let indexLeader = 0, lengthLeader = source.length; indexLeader < lengthLeader; indexLeader += 1) {
  // console.group(`leader index${indexLeader}`, source[indexLeader], source);
  for (let indexFollower = indexLeader + 1, lengthFollower = source.length; indexFollower < lengthFollower; indexFollower += 1) {
    // console.log('follower', indexFollower, source[indexFollower]);
    if (indexLeader === indexFollower) continue;
    if (source[indexLeader] === source[indexFollower]) {
      // console.log('-deleted', indexFollower, source[indexFollower], source);
      source.splice(indexFollower, 1);
      // console.log('*after deleted', indexFollower, source);
      indexLeader -= 1;
      indexFollower -= 1;
      lengthLeader -= 1;
      lengthFollower -= 1;
    }
  }
  // console.groupEnd(`index${indexLeader}`);
}

=> [1, 2, 3, 4, 5, 7]

단순화

const source = [1, 2, 3, 2, 4, 5, 3, 3, 7];

source.filter((value, index, self) => (self.indexOf(value) === index));

=> [1, 2, 3, 4, 5, 7]