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Automatically replace jQuery

Automatically find jQuery methods from existing projects and generate vanilla js alternatives.

demo.mp4


Why

I’ve been working on removing jQuery dependency from multiple projects including lightGallery lately. Most of the projects use only 15% to 20% or less than 30% of the jquery methods
And in most of the cases, I didn’t want to support all the edge cases or legacy browsers. The hardest part was finding the jQuery methods in the existing project and writing the alternative vanilla js┬ámethods without making much changes in the codebase. So I wrote this library which automatically finds jquery methods in any particular JavaScript file and generates readable, chainable vanilla js alternatives. This can also be useful if you want to generate your own utility┬ámethods similar to jQuery.

Installation and Usage

You can install replace-jquery using npm:

npm install -g replace-jquery
  • Find all jQuery methods from sample.js and write vanillaJs alternatives in out.js

replace-jquery src/sample.js out.js
  • Find all jQuery methods from all matching files and write vanillaJs alternatives in out.js

replace-jquery "src/*.js" out.js
  • Build vanillaJs alternatives for the all available jQuery methods

replace-jquery --build-all out.js
  • Build vanillaJs alternatives for the specified jQuery methods

replace-jquery --methods "addClass, removeClass, attr" -o utils.js

Please note that, the utility functions generated by replace-jquery are not completely equivalent to jQuery methods in all scenarios. Please consider this as a starting point and validate before you adopt it.

Basic Concepts

The generated vanilla JS methods are chainable and can be applied to all matching elements like jQuery.

Note: The below code is just to demonstrate the basics concepts and not covered all scenarios.

export class Utils {
  constructor(selector) {
    this.elements = Utils.getSelector(selector);
    this.element = this.get(0);
    return this;
  }

  static getSelector(selector, context = document) {
    if (typeof selector !== 'string') {
      return selector;
    }
    if (isId(selector)) {
      return document.getElementById(selector.substring(1))
    }
    return context.querySelectorAll(selector);
  }

  each(func) {
    if (!this.elements) {
      return this;
    }
    if (this.elements.length !== undefined) {
      [].forEach.call(this.elements, func);
    } else {
      func(this.element, 0);
    }
    return this;
  }

  siblings() {
    if (!this.element) {
      return this;
    }
    const elements = [].filter.call(
      this.element.parentNode.children,
      (child) => child !== this.element
    );
    return new Utils(elements);
  }

  get(index) {
    if (index !== undefined) {
      return this.elements[index];
    }
    return this.elements;
  }

  addClass(classNames = '') {
    this.each((el) => {
      // IE doesn't support multiple arguments
      classNames.split(' ').forEach((className) => {
        el.classList.add(className);
      });
    });
    return this;
  }
}

export default function $utils(selector) {
  return new Utils(selector);
}

Usage

<ul>
  <li class="jquery">jQuery</li>
  <li class="react">React</li>
  <li class="vue">Vue.js</li>
  <li class="angular">Angular</li>
  <li class="lit">Lit</li>
</ul>

.highlight {
  background-color: red;
  color: #fff;
}

$utils(".vue").siblings().addClass("highlight");

Demo – https://codepen.io/sachinchoolur/pen/oNWNdxE

You can see that the addClass method is depended on the each method, so if you generate addClass method using replace-jquery --methods "addClass" -o utils.js the output file will contain addClass and each methods.

Similarly, all the examples you see below, will add it’s dependencies when you generate it using replace-jquery

List of jQuery alternative methods in alphabetical order

addClass

addClass(classNames = '') {
  this.each((el) => {
    classNames.split(' ').forEach((className) => {
      el.classList.add(className);
    });
  });
  return this;
}

// Usage
$utils('ul li').addClass('myClass yourClass');
append

append(html) {
  this.each((el) => {
    if (typeof html === 'string') {
      el.insertAdjacentHTML('beforeend', html);
    } else {
      el.appendChild(html);
    }
  });
  return this;
}
attr

attr(name, value) {
  if (value === undefined) {
    if (!this.element) {
      return '';
    }
    return this.element.getAttribute(name);
  }
  this.each((el) => {
    el.setAttribute(name, value);
  });
  return this;
}
children

children() {
  return new Utils(this.element.children);
}
closest

closest(selector) {
  if (!this.element) {
    return this;
  }
  const matchesSelector =
    this.element.matches ||
    this.element.webkitMatchesSelector ||
    this.element.mozMatchesSelector ||
    this.element.msMatchesSelector;

  while (this.element) {
    if (matchesSelector.call(this.element, selector)) {
      return new Utils(this.element);
    }
    this.element = this.element.parentElement;
  }
  return this;
}
css

css(css, value) {
  if (value !== undefined) {
    this.each((el) => {
      Utils.setCss(el, css, value);
    });
    return this;
  }
  if (typeof css === 'object') {
    for (const property in css) {
      if (Object.prototype.hasOwnProperty.call(css, property)) {
        this.each((el) => {
          Utils.setCss(el, property, css[property]);
        });
      }
    }
    return this;
  }
  const cssProp = Utils.camelCase(css);
  const property = Utils.styleSupport(cssProp);
  return getComputedStyle(this.element)[property];
}
data

data(name, value) {
  return this.attr(`data-${name}`, value);
}
each

each(func) {
    if (!this.elements) {
        return this;
    }
    if (this.elements.length !== undefined) {
        [].slice.call(this.elements).forEach((el, index) => {
            func.call(el, el, index);
        });
    } else {
        func.call(this.element, this.element, 0);
    }
    return this;
}
empty

empty() {
  this.each((el) => {
    el.innerHTML = '';
  });
  return this;
}
eq

eq(index) {
  return new Utils(this.elements[index]);
}
find

find(selector) {
  return new Utils(Utils.getSelector(selector, this.element));
}
first

first() {
  if (this.elements && this.elements.length !== undefined) {
    return new Utils(this.elements[0]);
  }
  return new Utils(this.elements);
}
get

get() {
  return this.elements;
}
hasClass

hasClass(className) {
  if (!this.element) {
    return false;
  }
  return this.element.classList.contains(className);
}
height

height() {
  if (!this.element) {
    return 0;
  }
  const style = window.getComputedStyle(this.element, null);
  return parseFloat(style.height.replace('px', ''));
}
html

html(html) {
  if (html === undefined) {
    if (!this.element) {
      return '';
    }
    return this.element.innerHTML;
  }
  this.each((el) => {
    el.innerHTML = html;
  });
  return this;
}
index

index() {
  if (!this.element) return -1;
  let i = 0;
  do {
    i++;
  } while ((this.element = this.element.previousElementSibling));
  return i;
}
is

is(el) {
  if (typeof el === 'string') {
    return (
      this.element.matches ||
      this.element.matchesSelector ||
      this.element.msMatchesSelector ||
      this.element.mozMatchesSelector ||
      this.element.webkitMatchesSelector ||
      this.element.oMatchesSelector
    ).call(this.element, el);
  }
  return this.element === (el.element || el);
}
next

next() {
  if (!this.element) {
    return this;
  }
  return new Utils(this.element.nextElementSibling);
}
nextAll

nextAll(filter) {
  if (!this.element) {
    return this;
  }
  const sibs = [];
  let nextElem = this.element.parentNode.firstChild;
  do {
    if (nextElem.nodeType === 3) continue; // ignore text nodes
    if (nextElem === this.element) continue; // ignore this.element of target
    if (nextElem === this.element.nextElementSibling) {
      if (!filter || filter(this.element)) {
        sibs.push(nextElem);
        this.element = nextElem;
      }
    }
  } while ((nextElem = nextElem.nextSibling));
  return new Utils(sibs);
}
off

off(event) {
  if (!this.elements) {
    return this;
  }
  Object.keys(Utils.eventListeners).forEach((eventName) => {
    if (Utils.isEventMatched(event, eventName)) {
      Utils.eventListeners[eventName].forEach((listener) => {
        this.each((el) => {
          el.removeEventListener(
            eventName.split('.')[0],
            listener
          );
        });
      });
    }
  });

  return this;
}
offset

offset() {
  if (!this.element) {
    return {
      left: 0,
      top: 0,
    };
  }
  const box = this.element.getBoundingClientRect();
  return {
    top:
      box.top +
      window.pageYOffset -
      document.documentElement.clientTop,
    left:
      box.left +
      window.pageXOffset -
      document.documentElement.clientLeft,
  };
}
offsetParent

offsetParent() {
  if (!this.element) {
    return this;
  }
  return new Utils(this.element.offsetParent);
}
on

on(events, listener) {
  if (!this.elements) {
    return this;
  }
  events.split(' ').forEach((event) => {
    if (!Array.isArray(Utils.eventListeners[event])) {
      Utils.eventListeners[event] = [];
    }
    Utils.eventListeners[event].push(listener);
    this.each((el) => {
      el.addEventListener(event.split('.')[0], listener);
    });
  });

  return this;
}
one

one(event, listener) {
  this.each((el) => {
    new Utils(el).on(event, () => {
      new Utils(el).off(event);
      listener(event);
    });
  });
  return this;
}
outerHeight

outerHeight(margin) {
  if (!this.element) {
    return 0;
  }
  if (margin !== undefined) {
    let height = this.element.offsetHeight;
    const style = getComputedStyle(this.element);

    height +=
      parseInt(style.marginTop, 10) +
      parseInt(style.marginBottom, 10);
    return height;
  }
  return this.element.offsetHeight;
}
outerWidth

outerWidth(margin) {
  if (!this.element) {
    return 0;
  }
  if (margin !== undefined) {
    let width = this.element.offsetWidth;
    const style = window.getComputedStyle(this.element);

    width +=
      parseInt(style.marginLeft, 10) +
      parseInt(style.marginRight, 10);
    return width;
  }
  return this.element.offsetWidth;
}
parent

parent() {
  return new Utils(this.element.parentElement);
}
parentsUntil

parentsUntil(selector, filter) {
  if (!this.element) {
    return this;
  }
  const result = [];
  const matchesSelector =
    this.element.matches ||
    this.element.webkitMatchesSelector ||
    this.element.mozMatchesSelector ||
    this.element.msMatchesSelector;

  // match start from parent
  let el = this.element.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 new Utils(result);
}
position

position() {
  return {
    left: this.element.offsetLeft,
    top: this.element.offsetTop,
  };
}
prepend

prepend(html) {
  this.each((el) => {
    if (typeof html === 'string') {
      el.insertAdjacentHTML('afterbegin', html);
    } else {
      el.insertBefore(html, el.firstChild);
    }
  });
  return this;
}
prev

prev() {
  if (!this.element) {
    return this;
  }
  return new Utils(this.element.previousElementSibling);
}
prevAll

prevAll(filter) {
  if (!this.element) {
    return this;
  }
  const sibs = [];
  while ((this.element = this.element.previousSibling)) {
    if (this.element.nodeType === 3) {
      continue; // ignore text nodes
    }
    if (!filter || filter(this.element)) sibs.push(this.element);
  }
  return new Utils(sibs);
}
remove

remove() {
  this.each((el) => {
    el.parentNode.removeChild(el);
  });
  return this;
}
removeAttr

removeAttr(attributes) {
  const attrs = attributes.split(' ');
  this.each((el) => {
    attrs.forEach((attr) => el.removeAttribute(attr));
  });
  return this;
}
removeClass

removeClass(classNames) {
  this.each((el) => {
    // IE doesn't support multiple arguments
    classNames.split(' ').forEach((className) => {
      el.classList.remove(className);
    });
  });
  return this;
}
siblings

siblings() {
  if (!this.element) {
    return this;
  }
  const elements = Array.prototype.filter.call(
    this.element.parentNode.children,
    (child) => child !== this.element
  );
  return new Utils(elements);
}
text

text(text) {
  if (text === undefined) {
    if (!this.element) {
      return '';
    }
    return this.element.textContent;
  }
  this.each((el) => {
    el.textContent = text;
  });
  return this;
}
toggleClass

toggleClass(className) {
  if (!this.element) {
    return this;
  }
  this.element.classList.toggle(className);
}
trigger

trigger(event, detail) {
  if (!this.element) {
    return this;
  }
  const eventName = event.split('.')[0];
  const isNativeEvent =
    typeof document.body[`on${eventName}`] !== 'undefined';
  if (isNativeEvent) {
    this.each((el) => {
      el.dispatchEvent(new Event(eventName));
    });
    return this;
  }
  const customEvent = new CustomEvent(eventName, {
    detail: detail || null,
  });
  this.each((el) => {
    el.dispatchEvent(customEvent);
  });
  return this;
}
unwrap

unwrap() {
  this.each((el) => {
    const elParentNode = el.parentNode;

    if (elParentNode !== document.body) {
      elParentNode.parentNode.insertBefore(el, elParentNode);
      elParentNode.parentNode.removeChild(elParentNode);
    }
  });
  return this;
}
val

val(value) {
  if (!this.element) {
    return '';
  }
  if (value === undefined) {
    return this.element.value;
  }
  this.element.value = value;
}
width

width() {
  if (!this.element) {
    return 0;
  }
  const style = window.getComputedStyle(this.element, null);
  return parseFloat(style.width.replace('px', ''));
}
wrap

wrap(className) {
  this.each((el) => {
    const wrapper = document.createElement('div');
    wrapper.className = className;
    el.parentNode.insertBefore(wrapper, el);
    wrapper.appendChild(el);
  });
  return this;
}

Browser support – IE 11+

GitHub

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