solution.js

// 9
const removeEven1 = (arr) => arr.filter((el) => el % 2 !== 0);
const removeEven2 = (arr) => arr.filter((el) => el % 2);
removeEven1([1, 2, 4, 5, 10, 6, 3]);

// 10
const capitalize = (words) =>
  words.map((el) => el.charAt(0).toUpperCase() + el.slice(1));

// 11.
const evenOdd = (numbers) =>
  numbers.map((number) => (number % 2 === 0 ? "even" : "odd"));

evenOdd([1, 2, 3, 4, 5]);

// 12
const onlyAbove40 = (familyMembers) => {
  return familyMembers.reduce((acc, cur) => {
    if (cur.age > 40) acc.push(cur.familyMember);

    return acc;
  }, []);
};
onlyAbove40([
  {
    familyMember: "Uncle",
    age: 52,
    location: "San Diego, CA",
  },
  {
    familyMember: "Grandpa",
    age: 84,
    location: "San Francisco, CA",
  },
  {
    familyMember: "Sister",
    age: 19,
    location: "New York, NY",
  },
]);

// 14
const toObject = (strings) =>
  strings.reduce((acc, cur) => ({ ...acc, [cur]: true }), {});

toObject(["a", "b", "c", "d"]);

// 15
// forEach
function isSubset(arr1, arr2) {
  let subset = true;

  arr1.forEach(function (item) {
    if (!arr2.includes(item)) {
      subset = false;
    }
  });

  return subset;
}

// reduce
function isSubset(arr1, arr2) {
  return arr1.reduce(function (bool, nextItem) {
    if (bool === false) {
      return false;
    }

    return arr2.includes(nextItem);
  }, true);
}

// 16
const findMinimum = (arr) => {
  return arr.sort((a, b) => a - b)[1];
};

findMinimum([9, 2, 3, 6]);

// 17
const reArrange = (arr) => {
  return arr.sort();
}; // O(n) = n =>