Array
Array deduplication
function noRepeat(arr) {
return [...new Set(arr)];
}
Find the largest array
function arrayMax(arr) {
return Math.max(...arr);
}
Find the smallest array
function arrayMin(arr) {
return Math.min(...arr);
}
Returns the original array divided by an array whose size is the length
function chunk(arr, size = 1) {
return Array.from(
{
length: Math.ceil(arr.length / size),
},
(v, i) => arr.slice(i * size, i * size + size)
);
}
Check the number of occurrences of an element in the array
function countOccurrences(arr, value) {
return arr.reduce((a, v) => (v === value ? a + 1 : a + 0), 0);
}
Flatten array
function flatten(arr, depth = -1) {
if (depth === -1) {
return [].concat(
...arr.map((v) => (Array.isArray(v) ? this.flatten(v) : v))
);
}
if (depth === 1) {
return arr.reduce((a, v) => a.concat(v), []);
}
return arr.reduce(
(a, v) => a.concat(Array.isArray(v) ? this.flatten(v, depth - 1) : v),
[]
);
}
Compare two arrays and return the different elements
function diffrence(arrA, arrB) {
return arrA.filter((v) => !arrB.includes(v));
}
Return the same elements in two arrays
function intersection(arr1, arr2) {
return arr2.filter((v) => arr1.includes(v));
}
Delete n elements from the right
function dropRight(arr, n = 0) {
return n < arr.length ? arr.slice(0, arr.length - n) : [];
}
Intercept the first eligible element and subsequent elements
function dropElements(arr, fn) {
while (arr.length && !fn(arr[0])) arr = arr.slice(1);
return arr;
}
Returns the elements of the subscript interval nth in the array
function everyNth(arr, nth) {
return arr.filter((v, i) => i % nth === nth - 1);
}
Returns the nth element in the array
function nthElement(arr, n = 0) {
return (n >= 0 ? arr.slice(n, n + 1) : arr.slice(n))[0];
}
Returns the head element of the array
function head(arr) {
return arr[0];
}
Return the last element of the array
function last(arr) {
return arr[arr.length - 1];
}
Array shuffle
function shuffle(arr) {
let array = arr;
let index = array.length;
while (index) {
index -= 1;
let randomInedx = Math.floor(Math.random() * index);
let middleware = array[index];
array[index] = array[randomInedx];
array[randomInedx] = middleware;
}
return array;
}
Browser Object BOM
Determine whether the browser supports CSS properties
/** * Inform the browser of the specified CSS attributes supported by the browser*@param {String} key-The css attribute is the name of the attribute and does not need to be prefixed*@returns {String}-Supported attributes*/
function validateCssKey(key) {
const jsKey = toCamelCase(key); // Some css attributes are formed by hyphens
if (jsKey in document.documentElement.style) {
return key;
}
let validKey = "";
// The attribute name is in the form of prefix in js, and the attribute value is in the form of prefix in css
// After trying, Webkit can also be a lowercase first letter webkit
const prefixMap = {
Webkit: "-webkit-",
Moz: "-moz-",
ms: "-ms-",
O: "-o-",
};
for (const jsPrefix in prefixMap) {
const styleKey = toCamelCase(`${jsPrefix}-${jsKey}`);
if (styleKey in document.documentElement.style) {
validKey = prefixMap[jsPrefix] + key;
break;
}
}
return validKey;
}
/** * Convert a hyphenated string into a camel case string */
function toCamelCase(value) {
return value.replace(/-(\w)/g, (matched, letter) => {
return letter.toUpperCase();
});
}
/** * Check whether the browser supports a certain CSS attribute value (es6 version) *@param {String} key-The css attribute name to which the checked attribute value belongs*@param {String} value-CSS attribute value to be checked (without prefix) *@returns {String}-Returns the attribute value supported by the browser*/
function valiateCssValue(key, value) {
const prefix = ["-o-", "-ms-", "-moz-", "-webkit-", ""];
const prefixValue = prefix.map((item) => {
return item + value;
});
const element = document.createElement("div");
const eleStyle = element.style;
// The case of applying each prefix, and the case without a prefix should be applied at the end, depending on what kind of situation the browser is effective at the end
// This is the best last element in the prefix is ``
prefixValue.forEach((item) => {
eleStyle[key] = item;
});
return eleStyle[key];
}
/** * Check whether the browser supports a certain CSS attribute value*@param {String} key-The css attribute name to which the checked attribute value belongs*@param {String} value-CSS attribute value to be checked (without prefix) *@returns {String}-Returns the attribute value supported by the browser*/
function valiateCssValue(key, value) {
var prefix = ["-o-", "-ms-", "-moz-", "-webkit-", ""];
var prefixValue = [];
for (var i = 0; i < prefix.length; i++) {
prefixValue.push(prefix[i] + value);
}
var element = document.createElement("div");
var eleStyle = element.style;
for (var j = 0; j < prefixValue.length; j++) {
eleStyle[key] = prefixValue[j];
}
return eleStyle[key];
}
function validCss(key, value) {
const validCss = validateCssKey(key);
if (validCss) {
return validCss;
}
return valiateCssValue(key, value);
}
Return the current web page address
function currentURL() {
return window.location.href;
}
Get the scroll bar position
function getScrollPosition(el = window) {
return {
x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft,
y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop,
};
}
Get the parameters in the url
function getURLParameters(url) {
return url
.match(/([^?=&]+)(=([^&]*))/g)
.reduce(
(a, v) => (
(a[v.slice(0, v.indexOf("="))] = v.slice(v.indexOf("=") + 1)), a
),
{}
);
}
Page jump, whether it is recorded in history
function redirect(url, asLink = true) {
asLink ? (window.location.href = url) : window.location.replace(url);
}
Scroll bar back to top animation
function scrollToTop() {
const scrollTop =
document.documentElement.scrollTop || document.body.scrollTop;
if (scrollTop > 0) {
window.requestAnimationFrame(scrollToTop);
window.scrollTo(0, c - c / 8);
} else {
window.cancelAnimationFrame(scrollToTop);
}
}
Copy text
function copy(str) {
const el = document.createElement("textarea");
el.value = str;
el.setAttribute("readonly", "");
el.style.position = "absolute";
el.style.left = "-9999px";
el.style.top = "-9999px";
document.body.appendChild(el);
const selected =
document.getSelection().rangeCount > 0
? document.getSelection().getRangeAt(0)
: false;
el.select();
document.execCommand("copy");
document.body.removeChild(el);
if (selected) {
document.getSelection().removeAllRanges();
document.getSelection().addRange(selected);
}
}
Type of testing equipment
function detectDeviceType() {
return /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(
navigator.userAgent
)
? "Mobile"
: "Desktop";
}
Cookie
Increase
function setCookie(key, value, expiredays) {
var exdate = new Date();
exdate.setDate(exdate.getDate() + expiredays);
document.cookie =
key +
"=" +
escape(value) +
(expiredays == null ? "" : ";expires=" + exdate.toGMTString());
}
Delete
function delCookie(name) {
var exp = new Date();
exp.setTime(exp.getTime() - 1);
var cval = getCookie(name);
if (cval != null) {
document.cookie = name + "=" + cval + ";expires=" + exp.toGMTString();
}
}
Check
function getCookie(name) {
var arr,
reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
if ((arr = document.cookie.match(reg))) {
return arr[2];
} else {
return null;
}
}
Date
Timestamp converted to time
- The default is the current time conversion result
- isMs is whether the timestamp is in milliseconds
function timestampToTime(timestamp = Date.parse(new Date()), isMs = true) {
const date = new Date(timestamp * (isMs ? 1 : 1000));
return `${date.getFullYear()}-${
date.getMonth() + 1 < 10 ? "0" + (date.getMonth() + 1) : date.getMonth() + 1
}-${date.getDate()} ${date.getHours()}:${date.getMinutes()}:${date.getSeconds()}`;
}
Document Object DOM
Fixed scroll bar
/** * Function description: Some business scenarios, such as when a pop-up box appears, need to prohibit page scrolling. This is a solution compatible with Android and iOS to prohibit page scrolling*/
let scrollTop = 0;
function preventScroll() {
// Store the current scroll position
scrollTop = window.scrollY;
// Fix the position of the scrollable area. After the height of the scrollable area is 0, it cannot be scrolled.
document.body.style["overflow-y"] = "hidden";
document.body.style.position = "fixed";
document.body.style.width = "100%";
document.body.style.top = -scrollTop + "px";
// document.body.style['overscroll-behavior'] = 'none'
}
function recoverScroll() {
document.body.style["overflow-y"] = "auto";
document.body.style.position = "static";
// document.querySelector('body').style['overscroll-behavior'] = 'none'
window.scrollTo(0, scrollTop);
}
Determine whether the current position is at the bottom of the page
- The return value is true/false
function bottomVisible() {
return (
document.documentElement.clientHeight + window.scrollY >=
(document.documentElement.scrollHeight ||
document.documentElement.clientHeight)
);
}
Determine whether the element is within the visible range
- partiallyVisible is whether it is fully visible
function elementIsVisibleInViewport(el, partiallyVisible = false) {
const { top, left, bottom, right } = el.getBoundingClientRect();
return partiallyVisible
? ((top > 0 && top < innerHeight) ||
(bottom > 0 && bottom < innerHeight)) &&
((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth))
: top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth;
}
Get element css style
function getStyle(el, ruleName) {
return getComputedStyle(el, null).getPropertyValue(ruleName);
}
Enter full screen
function launchFullscreen(element) {
if (element.requestFullscreen) {
element.requestFullscreen();
} else if (element.mozRequestFullScreen) {
element.mozRequestFullScreen();
} else if (element.msRequestFullscreen) {
element.msRequestFullscreen();
} else if (element.webkitRequestFullscreen) {
element.webkitRequestFullScreen();
}
}
launchFullscreen(document.documentElement);
launchFullscreen(document.getElementById("id")); //An element enters the full screen
Exit Full Screen
function exitFullscreen() {
if (document.exitFullscreen) {
document.exitFullscreen();
} else if (document.msExitFullscreen) {
document.msExitFullscreen();
} else if (document.mozCancelFullScreen) {
document.mozCancelFullScreen();
} else if (document.webkitExitFullscreen) {
document.webkitExitFullscreen();
}
}
exitFullscreen();
Full screen event
document.addEventListener("fullscreenchange", function (e) {
if (document.fullscreenElement) {
console.log("Enter full screen");
} else {
console.log("Exit Full Screen");
}
});
Number
Digital thousandths division
function commafy(num) {
return num.toString().indexOf(".") !== -1
? num.toLocaleString()
: num.toString().replace(/(\d)(?=(?:\d{3})+$)/g, "$1,");
}
Generate random numbers
function randomNum(min, max) {
switch (arguments.length) {
case 1:
return parseInt(Math.random() * min + 1, 10);
case 2:
return parseInt(Math.random() * (max - min + 1) + min, 10);
default:
return 0;
}
}