Javascript select element in library

Javascript select element in library - javascript

I am working on a javascript library that will work like this: tex("element").print("hi"). Here is the code:
(function (window) {
var regex = {
Id : /^[#]\w+$/,
Class : /^[.]\w+$/,
Tag : /^\w+$/,
validSelector : /^([#]\w+|[.]\w+|\w+)$/
},
tex = function(selector){
//only some of the functions need to select an element
//EX:
// style: tex(selector).style(style);
//one that would not need a selector is the random number function:
// tex().random(from,to);
if (selector){
if (typeof selector === 'string'){
var valid = regex.validSelector.test(selector);
if( valid ){
if(regex.Id.test(selector)){
this = document.getElementById(selector);
}
if(regex.Class.test(selector)){
this = document.getElementByClass(selector);
}
if(regex.Tag.test(selector)){
this = document.getElementByTagName(selector);
}
}
}else if(typeof selector === 'object'){
this = selector;
}
//this = document.querySelector(selector);
// I could make a selector engine byt I only need basic css selectors.
}
};
tex.prototype = {
dit : function(){
this.innerHTML = 'Hi?!?!?!'
}
};
window.tex = tex;
})(window);
When I try to run the code I get an error that says, "Left side of argument is not a reference" referring to this = document.getElementById(selector);
Does anyone know what is wrong with my code?

Because you can not set this.
To do something that you are after, you just return this.
without using a prototype
var foo = function( selector ) {
this.print = function () {
console.group("in print");
console.log(this.elements[0].innerHTML);
console.groupEnd("in print");
return this;
}
this.printAll = function () {
console.group("in printAll");
for (var i=0; i<this.elements.length; i++) {
console.log(this.elements[i].innerHTML);
}
console.groupEnd("in printAll");
return this;
}
this.elements = document.querySelectorAll( selector );
return this;
}
console.group("id");
foo("#foofoo").print();
console.groupEnd("id");
console.group("class");
foo(".bar").printAll().print();
console.groupEnd("class");
JSFiddle
Basic example with prototype
(function () {
var basic = function (selector) {
this.elements = document.querySelectorAll(selector);
return this;
}
basic.prototype.print = function () {
console.group("in print");
console.log(this.elements[0].innerHTML);
console.groupEnd("in print");
return this;
}
basic.prototype.printAll = function () {
console.group("in printAll");
for (var i = 0; i < this.elements.length; i++) {
console.log(this.elements[i].innerHTML);
}
console.groupEnd("in printAll");
return this;
}
var foo = function (selector) {
return new basic(selector);
}
window.foo = foo;
})();
console.group("id");
foo("#foofoo").print();
console.groupEnd("id");
console.group("class");
foo(".bar").printAll().print();
console.groupEnd("class");
JSFiddle

Related

Can't call function on HTML element

I'm starting to write jQuery in Vanilla JS and my selectors work but when I call my append function on the HTML element I get an "is not a function" error.
var $ = function(){
this.select = function(input) {
if (input.split("")[0] == "#") {
input = input.slice(1, input.length)
return document.getElementById(input)
}
else if (input.split("")[0] == ".") {
input = input.slice(1, input.length)
return document.getElementsByClassName(input)
}
else {
return document.getElementsByTagName(input)
}
},
this.append = function(text) {
return this.innerhtml = this.innerhtml + text
}
};
my console attempts:
var myQuery = new $();
returns undefined
myQuery.select("#testspan")
returns my span tag here
myQuery.select("#testspan").append("hellohello")
returns error
VM2207:1 Uncaught TypeError: myQuery.select(...).append is not a function(…)

From your snippet the return of each of the select method return a DOM element (or collection). Really what you would like to do is called Chaining where the result of the method returns the original object. Therefore you can keep calling additional methods on the same object.
Now in your example you are going to need a collection of elements (nodes) somewhere the object can then access again. Here is a simple example.
var $ = function () {
this.nodes = [];
this.select = function (input) {
var self = this;
if (input.split("")[0] == "#") {
input = input.slice(1, input.length)
var node = document.getElementById(input);
if (node)
this.nodes.push(node);
}
else if (input.split("")[0] == ".") {
input = input.slice(1, input.length)
Array.prototype.slice.call(document.getElementsByClassName(input), 0).forEach(function (node) {
self.nodes.push(node);
});
}
else {
Array.prototype.slice.call(document.getElementsByTagName(input), 0).forEach(function (node) {
self.nodes.push(node);
});
}
return this;
},
this.append = function (text) {
this.nodes.forEach(function (i) {
i.innerHTML += text;
});
return this;
}
};
Sample Html:
<p id="test">This is test </p>
<p>This is number to</p>
Console (Chrome):
$ = new $()
$ {nodes: Array[0]}
$.select('p').append('hi')
Now a little issue here is you are (in the console) setting $ = new $() which effectivly overwrites the ability to call new $() again in the same script. I have provided a fiddle below that renames this to myQuery. Also changed that every time you call select will clear the node array.
Revised:
var myQuery = function () {
this.nodes = [];
this.select = function (input) {
this.nodes = [];
var self = this;
if (input.split("")[0] == "#") {
input = input.slice(1, input.length)
var node = document.getElementById(input);
if (node)
this.nodes.push(node);
}
else if (input.split("")[0] == ".") {
input = input.slice(1, input.length)
Array.prototype.slice.call(document.getElementsByClassName(input), 0).forEach(function (node) {
self.nodes.push(node);
});
}
else {
Array.prototype.slice.call(document.getElementsByTagName(input), 0).forEach(function (node) {
self.nodes.push(node);
});
}
return this;
},
this.append = function (text) {
this.nodes.forEach(function (i) {
i.innerHTML += text;
});
return this;
}
};
$ = new myQuery();
$.select('p').append(' test selection by tag name ');
$ = new myQuery();
$.select('.p1').append(' test selection by class ');
$ = new myQuery();
$.select('#p1').append(' test selection by id ');
$ = new myQuery();
$.select('#p2').append(' test selection by id ').append('and then chanined').select('.p2').append(' still chaining');
Fiddle: https://jsfiddle.net/kxwt9gmg/

You need to change up your approach a bit. You are wanting to store a result and call a method on it. You can ONLY call a method that that particular object has. That object you are returning, the raw html element, doesn't have that method. What you want to do is store the html element and then return an OBJECT that performs operations on what was stored. You can accomplish this using closure. For example:
function miniQuery(input){
function elementIterate(collection, action){
for (var i = elements.length -1; i >= 0; i-- ){
collection[i].style.display = action;
}
}
var isCollection = function(element){
if(element instanceof HTMLCollection){
return true
} else{
return false
}
}
function findElement(element){
if (element.startsWith("#")) {
// id element selector
return document.getElementById(element.substring(1));
} else if (element.startsWith(".")) {
// class element selector
return document.getElementsByClassName(element.substring(1));
} else {
// tag element selector
return document.getElementsByTagName(element);
};
}
if (input != undefined) {
var _this = this;
this.element = findElement(input);
var elements = findElement(input);
}
return {
append: function(content, position = 'beforeend'){
var elements = _this.element;
if (isCollection(elements)) {
for(var i = elements.length -1; i >= 0; i--){
elements[i].insertAdjacentHTML(position, content)
}
}else{
elements.insertAdjacentHTML(position, content);
}
}
}
}
function $(input){
return selector(input);
}
function selector(input){
var query = new miniQuery(input);
return query;
}

JavaScript - Understanding Method Chaining with return DOM elements

I'm trying to understand Javascript chaining with a return DOM element.
I'm not sure how to do this.
This is my code:
(function () {
function MyQuery(selector) {
if (!(this instanceof MyQuery)) {
return new MyQuery(selector);
}
this.nodes = document.querySelectorAll(selector);
for (var i = 0; i < this.nodes.length; i++) {
this.nodes[i] = this.nodes[i];
}
}
MyQuery.fn = MyQuery.prototype = {
parent: function () {
return this.nodes[0].parentNode;
},
color: function(setColor) {
this.nodes[0].style.color = setColor;
return this;
}
};
window.myQuery = window.$ = MyQuery;
})();
Call Methods:
myQuery(".mySpan").parent();
// Returns .. <div>
myQuery(".mySpan").parent().color("red");
// TypeError: myQuery(...).parent(...).color is not a function
HTML:
<div>
This DIV has some content.
<span class="mySpan">This is a span</span>
more content here.
</div>
I'm not sure why it would give me a TypeError, I have the parentNode which is the div all I want to do is set the color text of that div.

In order to make chainable methods available, you must not return a DOM element but rather an instance of your MyQuery class that has this method.
function MyQuery(selector) {
if (!(this instanceof MyQuery)) {
return new MyQuery(selector);
}
if (Array.isArray(selector)) {
this.nodes = selector;
} else {
this.nodes = [];
if (typeof selector == "string") {
var nodes = document.querySelectorAll(selector);
for (var i = 0; i < nodes.length; i++) {
this.nodes[i] = nodes[i];
}
}
}
}
MyQuery.prototype.parent = function () {
return new MyQuery([this.nodes[0].parentNode]);
};
MyQuery.prototype.color = function(setColor) {
this.nodes[0].style.color = setColor;
return this;
};

Protractor page object and element.all

I want my element.all() to return children with prototyped methods.
here's my code so far:
el.tags = function() {
var el = element.all(by.css('.tags > span'));
// return el;
return el.map(function(tag) {
tag.name = function() {
return tag.element(by.binding('tag.name')).getText()
}
tag.count = function() {
var text = tag.element(by.binding('tag.count')).getText()
return _.parseInt(text);
}
return tag;
});
}
the idea being once I call tags() the children have my prototyped methods immediately.
var tags = tags().filter(function(tag) {
return tag.name() === "foobar";
});
thanks!

How to "new" a returned function in Javascript

I am trying to simulate a namespace feature in Javascript.
var com = {};
com.domain = {};
com.domain.system = {};
com.domain.net = {};
com.domain.net.ip = {};
com.domain.net.ip.tcp = {};
com.domain.net.ip.udp = {};
com.domain.net.ip.ssl = {};
com.domain.util = {};
com.domain.util.timer = {};
com.domain.plugins = {};
com.domain.session = {};
com.domain.io = {};
com.domain.algorithm = {};
com.domain.debug = {};
This is the namespaces declaration. Later I will add functions to these namespaces.
This is my selector function:
For a convenient way to use namespaces, I add a function named $. This function will walk all namespaces in com. If the selected name exists, return the object.
function $ (selector) {
function digger (namespace, selector) {
for (var prop in namespace) {
if (typeof namespace[prop] == "array" || typeof namespace[prop] == "object") {
if (prop == selector) {
return namespace[prop];
}
var dig = digger(namespace[prop], selector);
if (dig != null) {
return dig;
}
} else {
if (prop == selector) {
return namespace[prop];
}
}
}
}
return digger (com, selector);
}
After that, I add a timer to namespace com.doamin.util.
com.domain.util.timer = function () {
this._handle = new InnerObj.SystemTimer(io);
return this;
};
com.domain.util.timer.prototype.expiresFromNow = function (seconds, cbHandler) {
this._handle.ExpiresFromNow (seconds, cbHandler);
};
com.domain.util.timer.prototype.wait = function (seconds, cbHandler) {
this._handle.Wait (seconds, cbHandler);
};
com.domain.util.timer.prototype.expiresAt = function (seconds, cbHandler) {
this._handle.Wait (seconds, cbHandler);
};
com.domain.util.timer.prototype.cancel = function () {
this._handle.Cancel ();
};
Usage:
1. var timer = new com.domain.util.timer (); OK
timer.expiresAt (1, {}); OK
2. var func = $("timer"); OK
var timer = new func (); OK
timer.expiresAt (1, {}); OK
But but but but but
var timer = new $("timer") (); NG
Can anyone tell me why the last new function is not working?

Try var timer = new ($("timer"))();.
Your question is not clear but I guess since $("timer") returns a function, you want a new instance of the result of $("timer") and not a new instance of $().

Can this jQuery be done in vanilla JS?

I've got this working on mobile devices, but because of the 32kb gzip-ed of jQuery I wonder if it's possible to create this code
$(document).ready(function() {
$('body').addClass('js');
var $menu = $('#menu'),
$menulink = $('.menu-link'),
$wrap = $('#wrap');
$menulink.click(function() {
$menulink.toggleClass('active');
$wrap.toggleClass('active');
return false;
});
});
can be written in no library dependany vanilla JavaScript.
Can it be done? Where would I start?

JQuery uses javascript/DOMscripting to create its framework. Everything JQuery does, can be done in basic scripting. For example $('body').addClass('js') can be written as:
document.querySelector('body').className += ' js';
And $menulink.toggleClass('active'); as something like
var current = $menulink.className.split(/\s+/)
,toggleClass = 'active'
,exist = ~current.indexOf(toggleClass)
;
current.splice(exist ? current.indexOf(toggleClass) : 0,
exist ? 1 : 0,
exist ? null : toggleClass);
$menulink.className = current.join(' ').replace(/^\s+|\s+$/,'');
That's why JQuery wrapped this kind of code.
This jsfiddle contains a working example using javascript without a framework. Besides that it demonstrates how to program your own element wrapper.
Where to start? You'll have to dive into javascript I suppose. Or check this SO-question

For modern browsers only.®
document.addEventListener('DOMContentLoaded', function() {
document.body.classList.add('js');
var wrap = document.getElementById('wrap');
var menuLinks = Array.prototype.slice.call(document.getElementsByClassName('menu-link'));
var toggleActive = function(element) {
element.classList.toggle('active');
};
menuLinks.forEach(function(menuLink) {
menuLink.addEventListener('click', function(e) {
menuLinks.forEach(toggleActive);
toggleActive(wrap);
}, false);
});
}, false);

var toggleClass = function (el, className) {
if(el) {
if(el.className.indexOf(className)) {
el.className = el.className.replace(className, '');
}
else {
el.className += ' ' + className;
}
}
};
document.addEventListener('DOMContentLoaded', function () {
document.body.className += ' js';
var $menu = document.querySelector('#menu'),
$menulink = document.querySelectorAll('.menu-link'),
$wrap = document.querySelector('#wrap');
$menulink.addEventListener('click', function (e) {
toggleClass($menulink, 'active');
toggleClass($wrap, 'active');
e.preventDefault();
});
});

There's always classList (workaround for incompatible browsers included).

Absolutely. Since jQuery is a subset of JavaScript (written entirely in JavaScript) any function you like can be duplicated. It's a matter of how much effort you want to put into it. Below is how I would duplicate the limited subset of jQuery in your post and it's reasonably cross-browser compatible (if a wee bit long...).
var Vanilla;
if (!Vanilla) {
Vanilla = {};
}
//execute this now to have access to it immediately.
(function () {
'use strict';
Vanilla.addHandler = function (elem, event, handler) {
if (elem.addEventListener) {
elem.addEventListener(event, handler, false);
} else if (elem.attachEvent) {
elem.attachEvent('on' + event, handler);
}
};
Vanilla.hasClass = function (elem, cssClass) {
var classExists = false;
//
if (elem && typeof elem.className === 'string' && (/\S+/g).test(cssClass)) {
classExists = elem.className.indexOf(cssClass) > -1;
}
//
return classExists;
};
Vanilla.addClass = function (elem, cssClass) {
if (elem && typeof elem.className === 'string' && (/\S+/g).test(cssClass)) {
//put spaces on either side of the new class to ensure boundaries are always available
elem.className += ' ' + cssClass + ' ';
}
};
Vanilla.removeClass = function (elem, cssClass) {
if (elem && typeof elem.className === 'string'&& (/\S+/g).test(cssClass)) {
//replace the string with regex
cssClass = new RegExp('\\b' + cssClass + '\\b', 'g');
elem.className = elem.className.replace(cssClass, '').replace(/^\s+/g, '').replace(/\s+$/g, ''); //trim className
}
};
Vanilla.toggleClass = function (elem, cssClass) {
if (Vanilla.hasClass(elem, cssClass)) {
Vanilla.removeClass(elem, cssClass);
} else {
Vanilla.addClass(elem, cssClass);
}
};
Vanilla.getElementsByClassName = function (cssClass) {
var nodeList = [],
classList = [],
allNodes = null,
i = 0,
j = 0;
if (document.getElementsByClassName1) {
//native method exists in browser.
nodeList = document.getElementsByClassName(cssClass);
} else {
//need a custom function
classList = cssClass.split(' ');
allNodes = document.getElementsByTagName('*');
for (i = 0; i < allNodes.length; i += 1) {
for (j = 0; j < classList.length; j += 1) {
if (Vanilla.hasClass(allNodes[i], classList[j])) {
nodeList.push(allNodes[i]);
}
}
}
}
return nodeList;
};
}());
//Now we have a proper window onload
Vanilla.addHandler(window, 'load', function () {
'use strict';
var body = document.body,
menu = document.getElementById('menu'),
menulink = [],
wrap = document.getElementById('wrap'),
i = 0,
menulinkClickHandler = function (e) {
var i = 0;
for (i = 0; i < menulink.length; i += 1) {
Vanilla.toggleClass(menulink[i], 'active');
}
Vanilla.toggleClass(wrap, 'active');
return false;
};
Vanilla.addClass(body, 'js');
menulink = Vanilla.getElementsByClassName('menu-link');
for (i = 0; i < menulink.length; i += 1) {
Vanilla.addHandler(menulink[i], 'click', menulinkClickHandler);
}
});

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Javascript select element in library - javascript

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Can't call function on HTML element

JavaScript - Understanding Method Chaining with return DOM elements

Protractor page object and element.all

How to "new" a returned function in Javascript

Can this jQuery be done in vanilla JS?

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