1. Date processing
1. Check if the date is valid
This method is used to check if the given date is valid:
const isDateValid = (...val) => !Number.isNaN(new Date(...val).valueOf());
isDateValid("December 17, 1995 03:24:00"); // true
2. Calculate the interval between two dates
This method is used to calculate the interval between two dates:
const dayDif = (date1, date2) => Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000)
dayDif(new Date("2021-11-3"), new Date("2022-2-1")) // 90
90 days until Chinese New Year~
3. Find the day of the year in which the date falls
This method is used to detect the day of the year in which the given date falls:
const dayOfYear = (date) => Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);
dayOfYear(new Date()); // 307
More than 300 days have passed in 2021~
4. Time formatting
This method can be used to convert time into the format of hours:minutes:seconds:
const timeFromDate = date => date.toTimeString().slice(0, 8);
timeFromDate(new Date(2021, 11, 2, 12, 30, 0)); // 12:30:00
timeFromDate(new Date()); // 返回当前时间 09:00:00
Two, string processing
1. Capitalize the first letter of the string
This method is used to capitalize the first letter of the English string:
const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1)
capitalize("hello world") // Hello world
2. Flip String
This method is used to flip a string and return the flipped string:
const reverse = str => str.split('').reverse().join('');
reverse('hello world'); // 'dlrow olleh'
3. Random string
This method is used to generate a random string:
const randomString = () => Math.random().toString(36).slice(2);
randomString();
4. Truncate the string
This method can truncate the string from the specified length:
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...'
5. Remove HTML from a string
This method is used to remove HTML elements from a string:
const stripHtml = html => (new DOMParser().parseFromString(html, 'text/html')).body.textContent || '';
3. Array processing
1. Remove duplicates from an array
This method is used to remove duplicates from an array:
const removeDuplicates = (arr) => [...new Set(arr)];
console.log(removeDuplicates([1, 2, 2, 3, 3, 4, 4, 5, 5, 6]));
2. Determine whether an array is empty
This method is used to determine whether an array is an empty array, and it will return a boolean value:
const isNotEmpty = arr => Array.isArray(arr) && arr.length > 0;
isNotEmpty([1, 2, 3]); // true
3. Merge two arrays
You can use the following two methods to merge two arrays:
const merge = (a, b) => a.concat(b);
const merge = (a, b) => [...a, ...b];
4. Digital operation
1. Determine whether a number is odd or even
This method is used to determine whether a number is odd or even:
const isEven = num => num % 2 === 0;
isEven(996);
2. Get the average of a set of numbers
const average = (...args) => args.reduce((a, b) => a + b) / args.length;
average(1, 2, 3, 4, 5); // 3
3. Get a random integer between two integers
This method is used to get a random integer between two integers
const random = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);
random(1, 50);
4. Rounding to specified digits
This method is used to round a number to specified digits:
const round = (n, d) => Number(Math.round(n + "e" + d) + "e-" + d)
round(1.005, 2) //1.01
round(1.555, 2) //1.56
Five, color operation
1. Convert RGB to hexadecimal mechanism
This method can convert an RGB color value into a hexadecimal value:
const rgbToHex = (r, g, b) => "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
rgbToHex(255, 255, 255); // '#ffffff'
2. Obtain a random hexadecimal color
This method is used to obtain a random hexadecimal color value:
const randomHex = () => `#${
Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, "0")}`;
randomHex();
6. Browser Operation
1. Copy content to the clipboard
This method uses
navigator.clipboard.writeText to copy text to the clipboard:
const copyToClipboard = (text) => navigator.clipboard.writeText(text);
copyToClipboard("Hello World");
2. Clear all cookies
This method can use document.cookie to access cookies and clear all cookies stored in the web page:
const clearCookies = document.cookie.split(';').forEach(cookie => document.cookie = cookie.replace(/^ +/, '').replace(/=.*/, `=;expires=${
new Date(0).toUTCString()};path=/`));
3. Get the selected text
This method gets the text selected by the user through the built-in getSelection property:
const getSelectedText = () => window.getSelection().toString();
getSelectedText();
4. Detect whether it is dark mode
This method is used to detect whether the current environment is dark mode, it is a boolean value:
const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches
console.log(isDarkMode)
5. Scroll to the top of the page
This method is used to return to the top of the page:
const goToTop = () => window.scrollTo(0, 0);
goToTop();
6. Determine whether the current tab is activated
This method is used to detect whether the current tab is activated:
const isTabInView = () => !document.hidden;
7. Determine whether the current device is an Apple device
This method is used to detect whether the current device is an Apple device:
const isAppleDevice = () => /Mac|iPod|iPhone|iPad/.test(navigator.platform);
isAppleDevice();
8. Whether to scroll to the bottom of the page
This method is used to judge whether the page has reached the bottom:
const scrolledToBottom = () => document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight;
9. Redirect to a URL
This method is used to redirect to a new URL:
const redirect = url => location.href = url
redirect("https://www.google.com/")
10. Open the print box of the browser
This method is used to open the print box of the browser:
const showPrintDialog = () => window.print()
7. Other operations
1. Random Boolean value
This method can return a random Boolean value. Use Math.random() to obtain a random number of 0-1. Compared with 0.5, there is a half probability of obtaining a true value or a false value.
const randomBoolean = () => Math.random() >= 0.5;
randomBoolean();
2. Variable exchange
The following forms can be used to exchange the values of two variables without the use of a third variable:
[foo, bar] = [bar, foo];
3. Get the type of variable
This method is used to get the type of a variable:
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
4. Conversion between Fahrenheit and Celsius
This method is used for conversion between Celsius and Fahrenheit:
const celsiusToFahrenheit = (celsius) => celsius * 9/5 + 32;
const fahrenheitToCelsius = (fahrenheit) => (fahrenheit - 32) * 5/9;
celsiusToFahrenheit(15); // 59
celsiusToFahrenheit(0); // 32
celsiusToFahrenheit(-20); // -4
fahrenheitToCelsius(59); // 15
fahrenheitToCelsius(32); // 0
5. Check whether the object is empty
This method is used to check whether a JavaScript object is empty:
const isEmpty = obj => Reflect.ownKeys(obj).length === 0 && obj.constructor === Object;