challeng10.js

const sortGrades = lst => {
  const grades = [
    "VB", "V0", "V0+", "V1", "V2", "V3", "V4", "V5", "V6", "V7",
    "V8", "V9", "V10", "V11", "V12", "V13", "V14", "V15", "V16", "V17"
  ];
  
  const result = new Array(grades.length).fill(null);
  if (lst.length === 0) {
    return [];
  }

  if (lst.length === 1) {
    return lst;
  }

  lst.forEach((elem) => {
    let itemIndex = grades.indexOf(elem);
    if (result.includes(elem)) {
      result.splice(itemIndex + 1, 1, elem);
    } else {
      result.splice(itemIndex, 1, elem);
    }
  });
  return result.filter((el) => el !== null);
};

// Test Cases
console.log(sortGrades(["V7", "V12", "V1"]));
//, ["V1", "V7", "V12"]
console.log(sortGrades(["V13", "V14", "VB", "V0"]));
//, ["VB", "V0", "V13", "V14"]
console.log(sortGrades(["V0+", "V0", "V16", "V2", "VB", "V6"]));
//, ["VB", "V0", "V0+", "V2", "V6", "V16"]
console.log(sortGrades(["V7"]));
//, ["V7"]

console.log(sortGrades(["VB", "VB"]));
//, ["VB","VB"]

console.log(sortGrades( ['V3','V0+', 'V0', 'V5', 'V1','V17']));
// ['V0', 'V0+', 'V1', 'V3', 'V5', 'V17']