nefe / You-Dont-Need-jQuery
- вторник, 2 апреля 2019 г. в 00:17:44
JavaScript
Examples of how to do query, style, dom, ajax, event etc like jQuery with plain javascript.
Frontend environments evolve rapidly nowadays and modern browsers have already implemented a great deal of DOM/BOM APIs which are good enough for production use. We don't have to learn jQuery from scratch for DOM manipulation or event handling. In the meantime, thanks to the spread of frontend libraries such as React, Angular and Vue, manipulating the DOM directly becomes anti-pattern, so that jQuery usage has never been less important. This project summarizes most of the alternatives in native Javascript implementation to jQuery methods, with IE 10+ support.
In place of common selectors like class, id or attribute we can use document.querySelector or document.querySelectorAll for substitution. The differences lie in:
document.querySelector returns the first matched elementdocument.querySelectorAll returns all matched elements as NodeList. It can be converted to Array using Array.prototype.slice.call(document.querySelectorAll(selector)); or any of the methods outlined in makeArraydocument.querySelectorAll will return [], whereas document.querySelector will return null.Notice:
document.querySelectoranddocument.querySelectorAllare quite SLOW, thus try to usedocument.getElementById,document.getElementsByClassNameordocument.getElementsByTagNameif you want to get a performance bonus.
1.0 Query by selector
// jQuery
$('selector');
// Native
document.querySelectorAll('selector');1.1 Query by class
// jQuery
$('.class');
// Native
document.querySelectorAll('.class');
// or
document.getElementsByClassName('class');1.2 Query by id
// jQuery
$('#id');
// Native
document.querySelector('#id');
// or
document.getElementById('id');1.3 Query by attribute
// jQuery
$('a[target=_blank]');
// Native
document.querySelectorAll('a[target=_blank]');1.4 Query in descendants
// jQuery
$el.find('li');
// Native
el.querySelectorAll('li');1.5 Sibling/Previous/Next Elements
All siblings
// jQuery
$el.siblings();
// Native - latest, Edge13+
[...el.parentNode.children].filter((child) =>
child !== el
);
// Native (alternative) - latest, Edge13+
Array.from(el.parentNode.children).filter((child) =>
child !== el
);
// Native - IE10+
Array.prototype.filter.call(el.parentNode.children, (child) =>
child !== el
);Previous sibling
// jQuery
$el.prev();
// Native
el.previousElementSibling;Next sibling
// jQuery
$el.next();
// Native
el.nextElementSibling;All previous siblings
// jQuery (optional filter selector)
$el.prevAll($filter);
// Native (optional filter function)
function getPreviousSiblings(elem, filter) {
var sibs = [];
while (elem = elem.previousSibling) {
if (elem.nodeType === 3) continue; // ignore text nodes
if (!filter || filter(elem)) sibs.push(elem);
}
return sibs;
}
All next siblings
// jQuery (optional selector filter)
$el.nextAll($filter);
// Native (optional filter function)
function getNextSiblings(elem, filter) {
var sibs = [];
var nextElem = elem.parentNode.firstChild;
do {
if (nextElem.nodeType === 3) continue; // ignore text nodes
if (nextElem === elem) continue; // ignore elem of target
if (nextElem === elem.nextElementSibling) {
if (!filter || filter(elem)) {
sibs.push(nextElem);
elem = nextElem;
}
}
} while(nextElem = nextElem.nextSibling)
return sibs;
}
An example of filter function:
function exampleFilter(elem) {
switch (elem.nodeName.toUpperCase()) {
case 'DIV':
return true;
case 'SPAN':
return true;
default:
return false;
}
}1.6 Closest
Return the first matched element by provided selector, traversing from current element up through its ancestors in the DOM tree.
// jQuery
$el.closest(selector);
// Native - Only latest, NO IE
el.closest(selector);
// Native - IE10+
function closest(el, selector) {
const matchesSelector = el.matches || el.webkitMatchesSelector || el.mozMatchesSelector || el.msMatchesSelector;
while (el) {
if (matchesSelector.call(el, selector)) {
return el;
} else {
el = el.parentElement;
}
}
return null;
}1.7 Parents Until
Get the ancestors of each element in the current set of matched elements, up to but not including the element matched by the selector, DOM node, or jQuery object.
// jQuery
$el.parentsUntil(selector, filter);
// Native
function parentsUntil(el, selector, filter) {
const result = [];
const matchesSelector = el.matches || el.webkitMatchesSelector || el.mozMatchesSelector || el.msMatchesSelector;
// match start from parent
el = el.parentElement;
while (el && !matchesSelector.call(el, selector)) {
if (!filter) {
result.push(el);
} else {
if (matchesSelector.call(el, filter)) {
result.push(el);
}
}
el = el.parentElement;
}
return result;
}1.8 Form
Input/Textarea
// jQuery
$('#my-input').val();
// Native
document.querySelector('#my-input').value;Get index of e.currentTarget between .radio
// jQuery
$('.radio').index(e.currentTarget);
// Native
Array.from(document.querySelectorAll('.radio')).indexOf(e.currentTarget);
or
Array.prototype.indexOf.call(document.querySelectorAll('.radio'), e.currentTarget);1.9 Iframe Contents
$('iframe').contents() returns contentDocument for this specific iframe
Iframe contents
// jQuery
$iframe.contents();
// Native
iframe.contentDocument;Iframe Query
// jQuery
$iframe.contents().find('.css');
// Native
iframe.contentDocument.querySelectorAll('.css');1.10 Get body
// jQuery
$('body');
// Native
document.body;1.11 Attribute getter and setter
Get an attribute
// jQuery
$el.attr('foo');
// Native
el.getAttribute('foo');Set an attribute
// jQuery
$el.attr('foo', 'bar');
// Native
el.setAttribute('foo', 'bar');Get a data- attribute
// jQuery
$el.data('foo');
// Native (use `getAttribute`)
el.getAttribute('data-foo');
// Native (use `dataset` if only need to support IE 11+)
el.dataset['foo'];1.12 Selector containing string (case-sensitive)
// jQuery
$("selector:contains('text')");
// Native
function contains(selector, text) {
var elements = document.querySelectorAll(selector);
return Array.from(elements).filter(function(element) {
return RegExp(text).test(element.textContent);
});
}2.1 CSS
Get style
// jQuery
$el.css('color');
// Native
// NOTE: Known bug, will return 'auto' if style value is 'auto'
const win = el.ownerDocument.defaultView;
// null means not to return pseudo styles
win.getComputedStyle(el, null).color;Set style
// jQuery
$el.css({ color: '#f01' });
// Native
el.style.color = '#f01';Get/Set Styles
Note that if you want to set multiple styles once, you could refer to setStyles method in oui-dom-utils package.
Add class
// jQuery
$el.addClass(className);
// Native
el.classList.add(className);Remove class
// jQuery
$el.removeClass(className);
// Native
el.classList.remove(className);has class
// jQuery
$el.hasClass(className);
// Native
el.classList.contains(className);Toggle class
// jQuery
$el.toggleClass(className);
// Native
el.classList.toggle(className);2.2 Width & Height
Width and Height are theoretically identical, take Height as example:
Window height
// window height
$(window).height();
// with scrollbar
window.document.documentElement.clientHeight;
// without scrollbar, behaves like jQuery
window.innerHeight;Document height
// jQuery
$(document).height();
// Native
const body = document.body;
const html = document.documentElement;
const height = Math.max(
body.offsetHeight,
body.scrollHeight,
html.clientHeight,
html.offsetHeight,
html.scrollHeight
);Element height
// jQuery
$el.height();
// Native
function getHeight(el) {
const styles = window.getComputedStyle(el);
const height = el.offsetHeight;
const borderTopWidth = parseFloat(styles.borderTopWidth);
const borderBottomWidth = parseFloat(styles.borderBottomWidth);
const paddingTop = parseFloat(styles.paddingTop);
const paddingBottom = parseFloat(styles.paddingBottom);
return height - borderBottomWidth - borderTopWidth - paddingTop - paddingBottom;
}
// accurate to integer(when `border-box`, it's `height - border`; when `content-box`, it's `height + padding`)
el.clientHeight;
// accurate to decimal(when `border-box`, it's `height`; when `content-box`, it's `height + padding + border`)
el.getBoundingClientRect().height;2.3 Position & Offset
Position
Get the current coordinates of the element relative to the offset parent.
// jQuery
$el.position();
// Native
{ left: el.offsetLeft, top: el.offsetTop }Offset
Get the current coordinates of the element relative to the document.
// jQuery
$el.offset();
// Native
function getOffset (el) {
const box = el.getBoundingClientRect();
return {
top: box.top + window.pageYOffset - document.documentElement.clientTop,
left: box.left + window.pageXOffset - document.documentElement.clientLeft
};
}2.4 Scroll Top
Get the current vertical position of the scroll bar for the element.
// jQuery
$(window).scrollTop();
// Native
(document.documentElement && document.documentElement.scrollTop) || document.body.scrollTop;3.1 Remove
Remove the element from the DOM.
// jQuery
$el.remove();
// Native
el.parentNode.removeChild(el);3.2 Text
Get text
Get the combined text contents of the element including their descendants,
// jQuery
$el.text();
// Native
el.textContent;Set text
Set the content of the element to the specified text.
// jQuery
$el.text(string);
// Native
el.textContent = string;3.3 HTML
Get HTML
// jQuery
$el.html();
// Native
el.innerHTML;Set HTML
// jQuery
$el.html(htmlString);
// Native
el.innerHTML = htmlString;3.4 Append
Append child element after the last child of parent element
// jQuery: unified syntax for DOMString and Node objects
$parent.append(newEl | '<div id="container">Hello World</div>');
// Native: different syntax
parent.insertAdjacentHTML('beforeend', '<div id="container">Hello World</div>');
parent.appendChild(newEl);
// Native (ES6-way): unified syntax
parent.append(newEl | '<div id="container">Hello World</div>');3.5 Prepend
// jQuery: unified syntax for DOMString and Node objects
$parent.prepend(newEl | '<div id="container">Hello World</div>');
// Native: different syntax
parent.insertAdjacentHTML('afterbegin', '<div id="container">Hello World</div>');
parent.insertBefore(newEl, parent.firstChild);
// Native (ES6-way): unified syntax
parent.prepend(newEl | '<div id="container">Hello World</div>');3.6 insertBefore
Insert a new node before the selected elements
// jQuery
$newEl.insertBefore(selector);
// Native (HTML string)
el.insertAdjacentHTML('beforebegin ', '<div id="container">Hello World</div>');
// Native (Element)
const el = document.querySelector(selector);
if (el.parentNode) {
el.parentNode.insertBefore(newEl, el);
}3.7 insertAfter
Insert a new node after the selected elements
// jQuery
$newEl.insertAfter(selector);
// Native (HTML string)
el.insertAdjacentHTML('afterend', '<div id="container">Hello World</div>');
// Native (Element)
const el = document.querySelector(selector);
if (el.parentNode) {
el.parentNode.insertBefore(newEl, el.nextSibling);
}3.8 is
Return true if it matches the query selector
// jQuery - Notice `is` also works with a function, an existing jQuery object or a DOM element, which are not of concern here
$el.is(selector);
// Native
el.matches(selector);3.9 clone
Create a deep copy of an element: it copies the matched element as well as all of its descendant elements and text nodes.
// jQuery. Sets parameter as `true` to indicate that event handlers should be copied along with the element.
$el.clone();
// Native
el.cloneNode();
3.10 empty
Remove all child nodes
// jQuery
$el.empty();
// Native
el.innerHTML = null;3.11 wrap
Wrap an HTML structure around each element
// jQuery
$('.inner').wrap('<div class="wrapper"></div>');
// Native
Array.from(document.querySelectorAll('.inner')).forEach.((el) => {
const wrapper = document.createElement('div');
wrapper.className = 'wrapper';
el.parentNode.insertBefore(wrapper, el);
el.parentNode.removeChild(el);
wrapper.appendChild(el);
});3.12 unwrap
Remove the parents of the set of matched elements from the DOM
// jQuery
$('.inner').unwrap();
// Native
Array.from(document.querySelectorAll('.inner')).forEach((el) => {
let elParentNode = el.parentNode;
if(elParentNode !== document.body) {
elParentNode.parentNode.insertBefore(el, elParentNode);
elParentNode.parentNode.removeChild(elParentNode);
}
});3.13 replaceWith
Replace each element in the set of matched elements with the provided new content
// jQuery
$('.inner').replaceWith('<div class="outer"></div>');
// Native
Array.from(document.querySelectorAll('.inner')).forEach((el) => {
const outer = document.createElement('div');
outer.className = 'outer';
el.parentNode.insertBefore(outer, el);
el.parentNode.removeChild(el);
});3.14 simple parse
Parse a string into HTML/SVG/XML
// jQuery
$(`<ol>
<li>a</li>
<li>b</li>
</ol>
<ol>
<li>c</li>
<li>d</li>
</ol>`);
// Native
range = document.createRange();
parse = range.createContextualFragment.bind(range);
parse(`<ol>
<li>a</li>
<li>b</li>
</ol>
<ol>
<li>c</li>
<li>d</li>
</ol>`);Fetch API is the new standard to replace XMLHttpRequest to do ajax. It works on Chrome and Firefox, you can use polyfills to make it work on legacy browsers.
Try github/fetch on IE9+ or fetch-ie8 on IE8+, fetch-jsonp to make JSONP requests.
4.1 Load data from the server and place the returned HTML into the matched element.
// jQuery
$(selector).load(url, completeCallback)
// Native
fetch(url).then(data => data.text()).then(data => {
document.querySelector(selector).innerHTML = data
}).then(completeCallback)For a complete replacement with namespace and delegation, refer to https://github.com/oneuijs/oui-dom-events
5.0 Document ready by DOMContentLoaded
// jQuery
$(document).ready(eventHandler);
// Native
// Check if the DOMContentLoaded has already been completed
if (document.readyState !== 'loading') {
eventHandler();
} else {
document.addEventListener('DOMContentLoaded', eventHandler);
}5.1 Bind an event with on
// jQuery
$el.on(eventName, eventHandler);
// Native
el.addEventListener(eventName, eventHandler);5.2 Unbind an event with off
// jQuery
$el.off(eventName, eventHandler);
// Native
el.removeEventListener(eventName, eventHandler);5.3 Trigger
// jQuery
$(el).trigger('custom-event', {key1: 'data'});
// Native
if (window.CustomEvent) {
const event = new CustomEvent('custom-event', {detail: {key1: 'data'}});
} else {
const event = document.createEvent('CustomEvent');
event.initCustomEvent('custom-event', true, true, {key1: 'data'});
}
el.dispatchEvent(event);Most of jQuery utilities are also found in the native API. Other advanced functions could be chosen from better utilities libraries, focusing on consistency and performance. Lodash is a recommended replacement.
6.1 Basic utilities
Determine whether the argument is an array.
// jQuery
$.isArray(array);
// Native
Array.isArray(array);Determine whether the argument is a window.
// jQuery
$.isWindow(obj);
// Native
function isWindow(obj) {
return obj !== null && obj !== undefined && obj === obj.window;
}Search for a specified value within an array and return its index (or -1 if not found).
// jQuery
$.inArray(item, array);
// Native
array.indexOf(item) > -1;
// ES6-way
array.includes(item);Determine if the argument passed is numerical.
Use typeof to decide the type or the type example for better accuracy.
// jQuery
$.isNumeric(item);
// Native
function isNumeric(value) {
return !isNaN(parseFloat(n)) && isFinite(n);
}Determine if the argument passed is a JavaScript function object.
// jQuery
$.isFunction(item);
// Native
function isFunction(item) {
if (typeof item === 'function') {
return true;
}
var type = Object.prototype.toString.call(item);
return type === '[object Function]' || type === '[object GeneratorFunction]';
}Check to see if an object is empty (contains no enumerable properties).
// jQuery
$.isEmptyObject(obj);
// Native
function isEmptyObject(obj) {
return Object.keys(obj).length === 0;
}Check to see if an object is a plain object (created using “{}” or “new Object”).
// jQuery
$.isPlainObject(obj);
// Native
function isPlainObject(obj) {
if (typeof (obj) !== 'object' || obj.nodeType || obj !== null && obj !== undefined && obj === obj.window) {
return false;
}
if (obj.constructor &&
!Object.prototype.hasOwnProperty.call(obj.constructor.prototype, 'isPrototypeOf')) {
return false;
}
return true;
}Merge the contents of two or more objects together into a new object, without modifying either argument. object.assign is part of ES6 API, and you could also use a polyfill.
// jQuery
$.extend({}, object1, object2);
// Native
Object.assign({}, object1, object2);Remove the white-space from the beginning and end of a string.
// jQuery
$.trim(string);
// Native
string.trim();Translate all items in an array or object to new array of items.
// jQuery
$.map(array, (value, index) => {
});
// Native
array.map((value, index) => {
});A generic iterator function, which can be used to seamlessly iterate over both objects and arrays.
// jQuery
$.each(array, (index, value) => {
});
// Native
array.forEach((value, index) => {
});Finds the elements of an array which satisfy a filter function.
// jQuery
$.grep(array, (value, index) => {
});
// Native
array.filter((value, index) => {
});Determine the internal JavaScript [Class] of an object.
// jQuery
$.type(obj);
// Native
function type(item) {
const reTypeOf = /(?:^\[object\s(.*?)\]$)/;
return Object.prototype.toString.call(item)
.replace(reTypeOf, '$1')
.toLowerCase();
}Merge the contents of two arrays together into the first array.
// jQuery, doesn't remove duplicate items
$.merge(array1, array2);
// Native, doesn't remove duplicate items
function merge(...args) {
return [].concat(...args)
}
// ES6-way, doesn't remove duplicate items
array1 = [...array1, ...array2]
// Set version, does remove duplicate items
function merge(...args) {
return Array.from(new Set([].concat(...args)))
}Return a number representing the current time.
// jQuery
$.now();
// Native
Date.now();Takes a function and returns a new one that will always have a particular context.
// jQuery
$.proxy(fn, context);
// Native
fn.bind(context);Convert an array-like object into a true JavaScript array.
// jQuery
$.makeArray(arrayLike);
// Native
Array.prototype.slice.call(arrayLike);
// ES6-way: Array.from() method
Array.from(arrayLike);
// ES6-way: spread operator
[...arrayLike];6.2 Contains
Check to see if a DOM element is a descendant of another DOM element.
// jQuery
$.contains(el, child);
// Native
el !== child && el.contains(child);6.3 Globaleval
Execute some JavaScript code globally.
// jQuery
$.globaleval(code);
// Native
function Globaleval(code) {
const script = document.createElement('script');
script.text = code;
document.head.appendChild(script).parentNode.removeChild(script);
}
// Use eval, but context of eval is current, context of $.Globaleval is global.
eval(code);6.4 parse
Parses a string into an array of DOM nodes.
// jQuery
$.parseHTML(htmlString);
// Native
function parseHTML(string) {
const context = document.implementation.createHTMLDocument();
// Set the base href for the created document so any parsed elements with URLs
// are based on the document's URL
const base = context.createElement('base');
base.href = document.location.href;
context.head.appendChild(base);
context.body.innerHTML = string;
return context.body.children;
}6.5 exists
exists
Check if an element exists in the DOM
// jQuery
if ($('selector').length) {
// exists
}
// Native
var element = document.getElementById('elementId');
if (typeof(element) != 'undefined' && element != null)
{
// exists
}A promise represents the eventual result of an asynchronous operation. jQuery has its own way to handle promises. Native JavaScript implements a thin and minimal API to handle promises according to the Promises/A+ specification.
7.1 done, fail, always
done is called when promise is resolved, fail is called when promise is rejected, always is called when promise is either resolved or rejected.
// jQuery
$promise.done(doneCallback).fail(failCallback).always(alwaysCallback)
// Native
promise.then(doneCallback, failCallback).then(alwaysCallback, alwaysCallback)7.2 when
when is used to handle multiple promises. It will resolve when all promises are resolved, and reject if either one is rejected.
// jQuery
$.when($promise1, $promise2).done((promise1Result, promise2Result) => {
});
// Native
Promise.all([$promise1, $promise2]).then([promise1Result, promise2Result] => {});7.3 Deferred
Deferred is a way to create promises.
// jQuery
function asyncFunc() {
const defer = new $.Deferred();
setTimeout(() => {
if(true) {
defer.resolve('some_value_computed_asynchronously');
} else {
defer.reject('failed');
}
}, 1000);
return defer.promise();
}
// Native
function asyncFunc() {
return new Promise((resolve, reject) => {
setTimeout(() => {
if (true) {
resolve('some_value_computed_asynchronously');
} else {
reject('failed');
}
}, 1000);
});
}
// Deferred way
function defer() {
const deferred = {};
const promise = new Promise((resolve, reject) => {
deferred.resolve = resolve;
deferred.reject = reject;
});
deferred.promise = () => {
return promise;
};
return deferred;
}
function asyncFunc() {
const defer = defer();
setTimeout(() => {
if(true) {
defer.resolve('some_value_computed_asynchronously');
} else {
defer.reject('failed');
}
}, 1000);
return defer.promise();
}8.1 Show & Hide
// jQuery
$el.show();
$el.hide();
// Native
// More detail about show method, please refer to https://github.com/oneuijs/oui-dom-utils/blob/master/src/index.js#L363
el.style.display = ''|'inline'|'inline-block'|'inline-table'|'block';
el.style.display = 'none';8.2 Toggle
Display or hide the element.
// jQuery
$el.toggle();
// Native
if (el.ownerDocument.defaultView.getComputedStyle(el, null).display === 'none') {
el.style.display = ''|'inline'|'inline-block'|'inline-table'|'block';
} else {
el.style.display = 'none';
}8.3 FadeIn & FadeOut
// jQuery
$el.fadeIn(3000);
$el.fadeOut(3000);
// Native fadeOut
function fadeOut(el, ms) {
if (ms) {
el.style.transition = `opacity ${ms} ms`;
el.addEventListener(
'transitionend',
function(event) {
el.style.display = 'none';
},
false
);
}
el.style.opacity = '0';
}
// Native fadeIn
function fadeIn(elem, ms) {
elem.style.opacity = 0;
if (ms) {
let opacity = 0;
const timer = setInterval(function() {
opacity += 50 / ms;
if (opacity >= 1) {
clearInterval(timer);
opacity = 1;
}
elem.style.opacity = opacity;
}, 50);
} else {
elem.style.opacity = 1;
}
}8.4 FadeTo
Adjust the opacity of the element.
// jQuery
$el.fadeTo('slow',0.15);
// Native
el.style.transition = 'opacity 3s'; // assume 'slow' equals 3 seconds
el.style.opacity = '0.15';8.5 FadeToggle
Display or hide the element by animating their opacity.
// jQuery
$el.fadeToggle();
// Native
el.style.transition = 'opacity 3s';
const { opacity } = el.ownerDocument.defaultView.getComputedStyle(el, null);
if (opacity === '1') {
el.style.opacity = '0';
} else {
el.style.opacity = '1';
}8.6 SlideUp & SlideDown
// jQuery
$el.slideUp();
$el.slideDown();
// Native
const originHeight = '100px';
el.style.transition = 'height 3s';
// slideUp
el.style.height = '0px';
// slideDown
el.style.height = originHeight;8.7 SlideToggle
Display or hide the element with a sliding motion.
// jQuery
$el.slideToggle();
// Native
const originHeight = '100px';
el.style.transition = 'height 3s';
const { height } = el.ownerDocument.defaultView.getComputedStyle(el, null);
if (parseInt(height, 10) === 0) {
el.style.height = originHeight;
} else {
el.style.height = '0px';
}8.8 Animate
Perform a custom animation of a set of CSS properties.
// jQuery
$el.animate({ params }, speed);
// Native
el.style.transition = 'all ' + speed;
Object.keys(params).forEach((key) =>
el.style[key] = params[key];
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