hw-js-09/javascript/hw.js

'use strict';

//Замыкания

const makeProfileTimer = (cb) => {
	const start = performance.now();
	cb();
	return () => performance.now() - start;
};
const timer = makeProfileTimer(() =>
	alert('Замеряем время работы этого alert')
);
alert(timer());

const makeSaver = (value) => () => value;
const saver = makeSaver(Math.random);
const value1 = saver();
const value2 = saver();
console.log(value1 === value2, 'value1 === value2');

const saver2 = makeSaver(
	() =>
		console.log('saved function called') ||
		[null, undefined, false, '', 0, Math.random()][Math.ceil(Math.random() * 6)]
);
const value3 = saver2();
const value4 = saver2();
console.log(value3 === value4, 'value3 === value4'); // тоже должно быть true

(function selfCountDown(n) {
	if (n === 0) return;
	setTimeout(() => {
		console.log(n);
		selfCountDown(n - 1);
	}, 1000);
})(5);

const myBind = function (fnBind, context, settings) {
	return function (...params) {
		let i = 0;
		const array = settings.map((settingsItem) => {
			if (settingsItem === undefined) {
				const paramsItem = params[i];
				i += 1;
				return paramsItem;
			} else {
				return settingsItem;
			}
		});
		return fnBind.apply(context, array);
	};
};

const pow5 = myBind(Math.pow, Math, [undefined, 5]);
const cube = myBind(Math.pow, Math, [undefined, 3]);
console.log(pow5(2)); // => 32, вызывает Math.pow(2,5), соотнесите с [undefined, 5]
console.log(cube(3)); // => 27
const chessMin = myBind(Math.min, Math, [
	undefined,
	4,
	undefined,
	5,
	undefined,
	8,
	undefined,
	9,
]);

console.log(chessMin(-1, -5, 3, 15));
const zeroPrompt = myBind(prompt, window, [undefined, '0']);
const someNumber = zeroPrompt('Введите число myBind'); // вызывает prompt("Введите число","0")\
console.log(
	myBind((...params) => params.join(''), null, [
		undefined,
		'b',
		undefined,
		undefined,
		'e',
		'f',
	])('a', 'c', 'd') === 'abcdef'
);