const truncateString = (string, length) => string.length < length ? string : `${string.slice(0, length - 3)}...`;
 
truncateString('Hi, I should be truncated because I am too loooong!', 36)   // 'Hi, I should be truncated because...'

const stripHtml = html => (new DOMParser().parseFromString(html,'text/html')).body.textContent || '';

const getFactorial = (n) => (n <= 1 ? 1 : n * getFactorial(n - 1));

const getFibonacci = (n, memo = {}) => memo[n] || (n <= 2 ? 1 : (memo[n] = getFibonacci(n - 1, memo) + getFibonacci(n - 2, memo)));

const getFactorial = (n) => (n <= 1 ? 1 : n * getFactorial(n - 1));

const isEven = num => num % 2 === 0;
 
isEven(996);

const average = (.. .args) => args.reduce((a, b) => a + b) / args.length;
 
average(1, 2, 3, 4, 5); // 3

const random = (min, max) => Math.floor(Math.random() * (max — min + 1) + min);
 
random(1, 50);

const random = (min, max) => Math.floor(Math.random() * (max — min + 1) + min);
 
random(1, 50);

const copyToArray = (arr) => [...arr];

const getUnique = (arr) => [...new Set(arr)];

const shuffle = (arr) => arr.sort(() => Math.random() - 0.5);

const groupBy = (arr, groupFn) =>   arr.reduce( (grouped, obj) => ({...grouped, [groupFn(obj)]: [...(grouped[groupFn(obj)] || []), obj], }),{});

const containSameValues= (arr1, arr2) =>   arr1.sort().join(',') === arr2.sort().join(',');

const isEmpty = obj => Reflect.ownKeys(obj).length === 0 && obj.constructor === Object;

[foo, bar] = [bar, foo];

const randomBoolean = () => Math.random() >= 0.5;
randomBoolean();

const trueTypeOf = (obj) => Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();
trueTypeOf(‘'); // string
trueTypeOf(0); // number
trueTypeOf(); // undefined
trueTypeOf(null); // null
trueTypeOf({}); // object
trueTypeOf([]); // array
trueTypeOf(0); // number
trueTypeOf(() => {}); // function

const toRGB= (hex) =>
    hex.
        replace(/^#?([a-f\d])([a-f\d])([a-f\d])$/i, (_, r, g, b) => `#${r}${r}${g}${g}$$`)
        .substring(1)
        .match(/.{2}/g)
        .map((x) => parseInt(x, 16));

const rgbToHex= (r,g,b) => "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
rgbToHex(255, 255, 255);  // '#ffffff'

const randomHex = () => `#${Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, "0")}`;
randomHex();

const toFahrenheit= (celsius) => (celsius * 9) / 5 + 32;

const toCelsius=  (fahrenheit) => (fahrenheit- 32) * 5 / 9;

const isTabInView = () => !document.hidden;

const isAppleDevice = () => /Mac|iPod|iPhone|iPad/.test(navigator.platform);
isAppleDevice();

const clearAllCookies = () => document.cookie.split(';').forEach((c) => (document.cookie = c.replace(/^ +/, '').replace(/=.*/, `=;expires=${new Date().toUTCString()};path=/`)));

const isAsyncFunction = (f) => Object.prototype.toString.call(f) === '[object AsyncFunction]';

const runningInBrowser = typeof window === 'object' && typeof document === 'object';

const runningInNode= typeof process !== 'undefined' && process.versions != null && process.versions.node != null;

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches
console.log(isDarkMode)

//方式一
const toTop = (element) =>
  element.scrollIntoView({ behavior: "smooth", block: "start" });

const toBottom = (element) =>
  element.scrollIntoView({ behavior: "smooth", block: "end" });

const goToTop = () => window.scrollTo(0, 0);
goToTop();

const scrolledToBottom = () => document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight;

const jsonToMap = (json) => new Map(Object.entries(JSON.parse(json)));

const generateUUID = (a) =>   a     ? (a ^ ((Math.random() * 16) >> (a / 4))).toString(16)     : ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(         /[018]/g,         generateUUID);

const redirect = url => location.href = url
redirect("https://www.google.com/")

const showPrintDialog = () => window.print()

const clearCookies = document.cookie.split(';').forEach(cookie => document.cookie = cookie.replace(/^ +/, '').replace(/=.*/, `=;expires=${new Date(0).toUTCString()};path=/`));