Нужна функция JS которая убирает все объекты с типом additional, а для basic очки уменьшить в двое

Question

Помогите написать функцию. Изменить нужно конкретно этот массив

const myLesson = [
  {lesson: 1, type: 'basic', points: 2},
  {lesson: 2, type: 'additional', points: 4},
  {lesson: 3, type: 'basic', points: 6},
  {lesson: 4, type: 'additional', points: 3},
  {lesson: 5, type: 'basic', points: 4},
  {lesson: 6, type: 'basic', points: 2},
  {lesson: 7, type: 'additional', points: 2},
  {lesson: 8, type: 'basic', points: 6},
  {lesson: 9, type: 'basic', points: 4},
  {lesson: 10, type: 'basic', points: 6},
  {lesson: 11, type: 'additional', points: 5}, 
  {lesson: 12, type: 'basic', points: 2}, 
  {lesson: 13, type: 'additional', points: 2}, 
  {lesson: 14, type: 'basic', points: 4},
  {lesson: 15, type: 'additional', points: 1},
  {lesson: 16, type: 'additional', points: 7},
];

Answer 1

Если массив небольшой и вам нужен более простой читабельный код, можно так (но массив будет перебираться два раза):

const myLesson = [
  {lesson: 1, type: 'basic', points: 2},
  {lesson: 2, type: 'additional', points: 4},
  {lesson: 3, type: 'basic', points: 6},
  {lesson: 4, type: 'additional', points: 3},
  {lesson: 5, type: 'basic', points: 4},
  {lesson: 6, type: 'basic', points: 2},
  {lesson: 7, type: 'additional', points: 2},
  {lesson: 8, type: 'basic', points: 6},
  {lesson: 9, type: 'basic', points: 4},
  {lesson: 10, type: 'basic', points: 6},
  {lesson: 11, type: 'additional', points: 5},
  {lesson: 12, type: 'basic', points: 2},
  {lesson: 13, type: 'additional', points: 2},
  {lesson: 14, type: 'basic', points: 4},
  {lesson: 15, type: 'additional', points: 1},
  {lesson: 16, type: 'additional', points: 7},
];

const myLessonProcessed = myLesson
  .filter(object => object.type === 'basic')
  .map(object => (object.points /= 2, object));

console.log(myLessonProcessed);

Если нужно эффективнее и можно чуть сложнее, тогда можно так (массив будет перебираться один раз):

const myLesson = [
  {lesson: 1, type: 'basic', points: 2},
  {lesson: 2, type: 'additional', points: 4},
  {lesson: 3, type: 'basic', points: 6},
  {lesson: 4, type: 'additional', points: 3},
  {lesson: 5, type: 'basic', points: 4},
  {lesson: 6, type: 'basic', points: 2},
  {lesson: 7, type: 'additional', points: 2},
  {lesson: 8, type: 'basic', points: 6},
  {lesson: 9, type: 'basic', points: 4},
  {lesson: 10, type: 'basic', points: 6},
  {lesson: 11, type: 'additional', points: 5},
  {lesson: 12, type: 'basic', points: 2},
  {lesson: 13, type: 'additional', points: 2},
  {lesson: 14, type: 'basic', points: 4},
  {lesson: 15, type: 'additional', points: 1},
  {lesson: 16, type: 'additional', points: 7},
];

const myLessonProcessed = myLesson
  .reduce((array, object) => {
    if (object.type === 'basic') {
      object.points /= 2;
      array.push(object);
    }
    return array;
  }, []);

console.log(myLessonProcessed);

Если нужно изменить сам массив, не создавая копию, тогда можно так:

const myLesson = [
  {lesson: 1, type: 'basic', points: 2},
  {lesson: 2, type: 'additional', points: 4},
  {lesson: 3, type: 'basic', points: 6},
  {lesson: 4, type: 'additional', points: 3},
  {lesson: 5, type: 'basic', points: 4},
  {lesson: 6, type: 'basic', points: 2},
  {lesson: 7, type: 'additional', points: 2},
  {lesson: 8, type: 'basic', points: 6},
  {lesson: 9, type: 'basic', points: 4},
  {lesson: 10, type: 'basic', points: 6},
  {lesson: 11, type: 'additional', points: 5},
  {lesson: 12, type: 'basic', points: 2},
  {lesson: 13, type: 'additional', points: 2},
  {lesson: 14, type: 'basic', points: 4},
  {lesson: 15, type: 'additional', points: 1},
  {lesson: 16, type: 'additional', points: 7},
];

for (let i = 0; i < myLesson.length; i++) {
  if (myLesson[i].type === 'basic') {
    myLesson[i].points /= 2;
  } else {
    myLesson.splice(i, 1);
    i--;
  }
}

console.log(myLesson);

Answer 2

Для изменения текущего массива я бы сначала объявил его не const, а let. Тогда функция может выглядеть так:

let myLesson = [
  {lesson: 1, type: 'basic', points: 2},
  {lesson: 2, type: 'additional', points: 4},
  {lesson: 3, type: 'basic', points: 6},
  {lesson: 4, type: 'additional', points: 3},
  {lesson: 5, type: 'basic', points: 4},
  {lesson: 6, type: 'basic', points: 2},
  {lesson: 7, type: 'additional', points: 2},
  {lesson: 8, type: 'basic', points: 6},
  {lesson: 9, type: 'basic', points: 4},
  {lesson: 10, type: 'basic', points: 6},
  {lesson: 11, type: 'additional', points: 5},
  {lesson: 12, type: 'basic', points: 2},
  {lesson: 13, type: 'additional', points: 2},
  {lesson: 14, type: 'basic', points: 4},
  {lesson: 15, type: 'additional', points: 1},
  {lesson: 16, type: 'additional', points: 7},
];

myLesson = changeArr(myLesson)

function changeArr(arr){
  return arr.filter( el => el.type !== 'additional')
            .map( el => {
              if (el.type === 'basic') el.points = el.points / 2
              return el
            })
}

console.log(myLesson)

БЛОГ НА HUSL

Нужна функция JS которая убирает все объекты с типом additional, а для basic очки уменьшить в двое

Ответы (2 шт):