readme.md

Challenge: Phone Number Directory

Instructions

You are building a phone number directory application. Implement a function called phoneNumberDirectory that takes an array of phone numbers as input and returns a Map with names as keys and corresponding phone numbers as values.

Function Signature

/**
 * Builds a phone number directory from an array of phone numbers.
 *
 * @param {string[]} phoneNumbers - An array of phone numbers in the format "Name:PhoneNumber".
 * @returns {Map<string, string>} - A Map with names as keys and corresponding phone numbers as values.
 */
function phoneNumberDirectory(phoneNumbers: string[]): Map<string, string>

Examples

const phoneNumbers = [
  'John:123-456-7890',
  'Jane:987-654-3210',
  'Joe:555-555-5555',
];

console.log(phoneNumberDirectory(phoneNumbers));
// Output: Map { 'John' => '123-456-7890', 'Jane' => '987-654-3210', 'Joe' => '555-555-5555' }

Constraints

• The input array elements should be formatted as NAME:PHONENUMBER

Hints

• Loop through the input array and use the split() method to separate the name and phone number in each element of the phoneNumbers array before adding to the map

Solutions

Click For Solution

function phoneNumberDirectory(phoneNumbers) {
  const directory = new Map();

  for (const entry of phoneNumbers) {
    const [name, phoneNumber] = entry.split(':');
    directory.set(name, phoneNumber);
  }

  return directory;
}

Explanation

• Create a new Map called directory
• Iterate through the phoneNumbers array using a for...of loop
• Use the split() method to separate the name and phone number from each entry using the colon : as the separator
• Set each name as the key and its corresponding phone number as the value in the Map
• Return the directory, which now contains the phone number directory

Test Cases

test('Building a phone number directory from an array of phone numbers', () => {
  const phoneNumbers = [
    'John:123-456-7890',
    'Jane:987-654-3210',
    'Joe:555-555-5555',
  ];

  const result = phoneNumberDirectory(phoneNumbers);

  expect(result.get('John')).toBe('123-456-7890');
  expect(result.get('Jane')).toBe('987-654-3210');
  expect(result.get('Joe')).toBe('555-555-5555');
});