exercise

index.js

// 1. Test your concepts of arrays by determining the location of an item in an array.
const indexOf = (arr, item) => {
	// Your code here
	for (let i = 0; i < arr.length; i++) {
		if (arr[i] === item) return i;
	}

	return -1;
};

// 2. Evaluate your concepts by populating an array.
const sum = (arr) => {
	// Your code here
	return arr.reduce((acc, cur) => (acc += cur));
};

// 3. Evaluate yourself by returning a new array after removing all instances of a value from an array.
// Returns a new array
const remove = (arr, item) => {
	// Your code here
	return arr.filter((el) => el !== item);
};

// 4. Evaluate yourself by adding an item to the end of an array
const append = (arr, item) => {
	// Your code here
	arr.push(item);
	return arr;
};

// 5. Evaluate yourself by removing the last item of an array
const truncate = (arr) => {
	// Your code here
	arr.pop();
	return arr;
};

// 6. Test yourself by Adding an item at the beginning of an array.
// Prepends to the original array
const prepend = (arr, item) => {
	// Your code here
	arr.unshift(item);
	return arr;
};

// 7. Test yourself by removing the first item of an array.
// Modifies the original array
const curtail = (arr) => {
	// Your code here
	arr.shift();
	return arr;
};

// 8. Test yourself by adding an item anywhere in an array.
// Inserts an element in the original array
const insert = (arr, item, index) => {
	// Your code here
	arr.splice(index, 0, item);
	return arr;
};

// 9.  Test yourself by counting the occurrences of an item in an array.
const count = (arr, item) => {
	// Your code here
	return arr.reduce((acc, cur) => (cur === item ? acc++ : acc), 0);
};

// 10. Test yourself by finding the duplicates in an array.
const duplicates = (arr) => {
	// Your code here
	const count = new Set();
	return arr.filter((num) => count.size === count.add(num).size);
};

// 11. Test yourself by Squaring each number in an array.
const square = (arr) => {
	// Your code here
	return arr.map((el) => Math.pow(el, 2));
};

// 12. Test yourself by finding all occurrences of an item in an array.

const findAllOccurrences = (arr, target) => {
	let result = [];

	for (let i = 0; i < arr.length; i++) {
		if (arr[i] === target) result.push(i);
	}
	return result;
};

// Exercise 2: Make Maximum Donuts
const maxDonuts = (recipe, quantity) => {
	let rs = 0;
	for (let i of Object.keys(recipe)) {
		if (Math.floor(quantity[i] / recipe[i]) < 1) return 0;

		if (Math.floor(quantity[i] / recipe[i]) < rs || rs === 0)
			rs = Math.floor(quantity[i] / recipe[i]);
	}

	return rs;
};

// Exercise 3: Calculate Score
const records = [
	{
		value: 24,
		gender: 'BOYS',
	},
	{
		value: 42,
		gender: 'BOYS',
	},
	{
		value: 85,
		gender: 'GIRLS',
	},
	{
		value: 12,
		gender: 'GIRLS',
	},
	{
		value: 10,
		gender: 'BOYS',
	},
];
const sumOfValues = records.reduce(
	(acc, cur) => (cur.gender === 'BOYS' ? (acc += cur.value) : acc),
	0
);

// Evaluate your string concepts by reducing the consecutive duplicate characters to the desired minimum.
const reduceString = function (str, amount) {
	var re = new RegExp('(.)(?=\\1{' + amount + '})', 'g');
	return str.replace(re, '');
};

// Test yourself by reversing a string.
const reverseString = (str) => str.split('').reverse().join('');