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Challenge: Display Likes

Instructions

Write a function called displayLikes that takes in an array of names and returns a string of who likes the post.

The function should return a string formatted as follows:

  • If no one likes it, it should return 'no one likes this'
  • If one person likes it, it should return '{name} likes this'
  • If two people like it, it should return '{name1} and {name2} like this'
  • If three people like it, it should return '{name1}, {name2} and {name3} like this'
  • If more than three people like it, it should return '{name1}, {name2} and {x} others like this'

Function Signature

/**
 * Returns a string of who likes the post.
 * @param {string[]} names - The names of the people who like the post.
 * @returns {string} - A string of who likes the post.
 */
function displayLikes(names: string[]): string;

Examples

displayLikes([]) // 'no one likes this'
displayLikes(['Peter']) // 'Peter likes this'
displayLikes(['Jacob', 'Alex']) // 'Jacob and Alex like this'
displayLikes(['Max', 'John', 'Mark']) // 'Max, John and Mark like this'
displayLikes(['Alex', 'Jacob', 'Mark', 'Max']) // 'Alex, Jacob and 2 others like this'
displayLikes(['Alex', 'Jacob', 'Mark', 'Max', 'Jill']) // 'Alex, Jacob and 3 others like this'

Constraints

  • The input array will only contain strings

Hints

Solutions

Click For Solution 
function displayLikes(names) {
  const length = names.length;

  if (length === 0) {
    return 'no one likes this';
  } else if (length === 1) {
    return `${names[0]} likes this`;
  } else if (length === 2) {
    return `${names[0]} and ${names[1]} like this`;
  } else if (length === 3) {
    return `${names[0]}, ${names[1]} and ${names[2]} like this`;
  } else {
    return `${names[0]}, ${names[1]} and ${length - 2} others like this`;
  }
}

Explanation

This is pretty simple as it just requires a bunch of if statements. We could also use a switch statement here, but it would be a bit more verbose.

  • Get the length of the array and then check if it's 0, 1, 2, 3, or more. Depending on the length, we return the appropriate string.
  • If there are more than 3 names, we return the first two names, and then the length minus 2 for the number of others.

Test Cases

test('Display Likes', () => {
  expect(displayLikes([])).toEqual('no one likes this');
  expect(displayLikes(['Peter'])).toEqual('Peter likes this');
  expect(displayLikes(['Jacob', 'Alex'])).toEqual('Jacob and Alex like this');
  expect(displayLikes(['Max', 'John', 'Mark'])).toEqual(
    'Max, John and Mark like this'
  );
  expect(displayLikes(['Alex', 'Jacob', 'Mark', 'Max'])).toEqual(
    'Alex, Jacob and 2 others like this'
  );
  expect(displayLikes(['Alex', 'Jacob', 'Mark', 'Max', 'Jill'])).toEqual(
    'Alex, Jacob and 3 others like this'
  );
});