bird-watcher.js

// @ts-check
//
// The line above enables type checking for this file. Various IDEs interpret
// the @ts-check directive. It will give you helpful autocompletion when
// implementing this exercise.

/**
 * Calculates the total bird count.
 *
 * @param {number[]} birdsPerDay
 * @returns {number} total bird count
 */
export function totalBirdCount(birdsPerDay) {
  let total = 0;

  for (let i = 0; i < birdsPerDay.length; i++) {
    total += birdsPerDay[i];
  }
  return total;
}

/**
 * Calculates the total number of birds seen in a specific week.
 *
 * @param {number[]} birdsPerDay
 * @param {number} week
 * @returns {number} birds counted in the given week
 */
export function birdsInWeek(birdsPerDay, week) {
  const weekIndex = (week - 1) * 7;
  return totalBirdCount(birdsPerDay.slice(weekIndex, weekIndex + 7));
}

/**
 * Fixes the counting mistake by increasing the bird count
 * by one for every second day.
 *
 * @param {number[]} birdsPerDay
 * @returns {number[]} corrected bird count data
 */
export function fixBirdCountLog(birdsPerDay) {
  for (let i = 0; i < birdsPerDay.length; i++) {
    if (i % 2 === 0) {
      birdsPerDay.splice(i, 1, birdsPerDay[i] + 1)
    }
  } 
  return birdsPerDay
}