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#Listo with jQuery

Today we will be turning our HTML / CSS assessment into a real life web application using jQuery named Listo!

With Listo, users will be able to:

*Create new list items. *Move the items from 'New' to 'In Progress' to 'Archived' to deleted. *Save list items to our browsers local storage so that it persists, even if we close the browser.

#Step 1 ###Our Environment

We are going to be setting up the environment from scratch, so that we can get used to building our projects.

First, fork and clone this repo, so that we can access this README during our development. For the sake of simplicity we have created the index.html file, so no need to change it yet.

After that, let's create a folder called 'app'. This is where we will store the guts of our app. Inside the app folder let's make a folder called 'scripts'. This is where we will store our JavaScript.

Inside the js folder we will create our main javascript named something awesome like 'app.js'.

Then inside the app folder we will create a folder called 'Styles', this is where we will store our CSS files. Inside the 'Styles' folder let's make a file called main.css so that we have a place to style things.

Now that we've made our basic files, we want to get them all hooked together in our index.html file.

*Remember: a lot of times we get errors in the beginning of a project is because the files are not properly linked. *

Remember: your browser will read your index.html from top-to-bottom, left-to-right. This means if you put your jquery under your app.js file you will end up with an error.

#Step 2 ###Time For jQuery

Now that we have our environment set up, and our markup written, it's time to get into the JavaScript with jQuery.

The first thing we want to do is go into our app.js file and create our document ready function:

app.js

$(document).ready(function() {//ALL CODE GOES IN HERE});

This essentially allows us to load our app when the document loads. It's a weird jQuery thing, but it's what we do. Remember, all of the code in our app.js will go within the {} of the above function.

###Basic Architecture

We are going to be creating a todo list. So the easiest way to store a list of things is to create an array!

app.js

var listo = [];

Listo will be our main array for storing tasks.

Now, we don't want to just store strings. So instead we will store Task objects into our array. Because our users are going to be making a lot of Tasks we should perhaps streamline the object creating process with a constructor!

app.js

var Task = function(task) {
	this.task = task;
	this.id = 'new';
}

We now have an array to push our tasks onto, and a task constructor so our users can create object tasks for their lists.

The next thing we want is the ability for a user to write a todo task into our index.html and save it to the array.

Let's hop over to our index.html and create a space for them to type in their list items.

index.html

    <form id="newTaskForm">
    	<label>New Item</label>
        <input id="newItemInput" placeholder="new task">
        <button id="saveNewItem">Save</button>
        <button id="cancel">Cancel</button>
    </form>

This will create a form with a save and cancel button. We want to give the save and cancel buttons IDs so that we can call them with jQuery. We also want to give the form an ID so it can be accessed as well.

You will come to see that most elements in our html will have an ID. That is so that jQuery has a lot of hooks to make contact with what it is looking to manipulate.

###Making our addTask function

When we enter something into the input field and hit save, we want to create an object and push it to our array.

Let's make a function to do that for us.

app.js

var addTask = function(task) {};

Cool, a blank function named 'addTask'!

Now, we don't want people to be able to create blank todo tasks, that would be a little frustrating. Let's put a conditional in the function so that it only runs if our task is there.

app.js

var addTask = function(task) {
	if(task) {

	}
};

Now our code will only run if 'task' is truthy. Empty tasks are not truthy since they're just empty strings.

Next we want to call our task constructor and fill it with the new task, then we will push the new task to listo, and save it.

app.js

var addTask = function(task) {
	if(task) {
		task = new Task(task);
		listo.push(task);
	}
};

Now there are a few things we should add to this function to make it work correctly. First we want the input form to clear after we submit it, which currently isn't happening. Then we want to make it so we can show our new list item in our index.html.

app.js

var addTask = function(task) {
	if(task) {
		task = new Task(task);
		listo.push(task);

		$('#newItemInput').val('');
		$('#newList').append('<a href="#" class="" id="item"><li class="list-group-item">' + task.task + '<span class="arrow pull-right"><i class="glyphicon glyphicon-arrow-right"></span></li></a>');

	}
};

Let's also create a way to toggle our form so we can see how jQuery affects our app's design.

First we should make it so that our newTaskForm is hidden when the document loads. Let's put this near the top of our document so that it loads correctly.

app.js

$('#newTaskForm').hide();

Then let's add the fade toggle so that our New button will hide and show the input form at the same time.

app.js

var addTask = function(task) {
	if(task) {
		task = new Task(task);
		listo.push(task);

		$('#newItemInput').val('');

		$('#newList').append('<a href="#finish" class="" id="item"><li class="list-group-item">' + task.task + '<span class="arrow pull-right"><i class="glyphicon glyphicon-arrow-right"></span></li></a>');

	}
	$('#newTaskForm,  #newListItem').fadeToggle('fast', 'linear');

};

We added a new ID here called newListItem. We will need to attach that to a button in the index.html file so that we can toggle the form.

index.html

<div class='new-item-header'>
	<button href="#" class="pull-right pencil" id="newListItem" style="">New</button>
</div>

Let's also create a div underneath all of that with the id of newList so that our addTask function can append the new items into the DOM.

index.html

<div id="newList">
	New List
</div>

We will now call a jQuery event that calls the addTask function when we click the saveNewItem button.

app.js

$('#saveNewItem').on('click', function (e) {
    e.preventDefault();
    var task = $('#newItemInput').val().trim();
    addTask(task);
});

Finally let's make it so that we can open and close the new task form with the newListItem and Cancel button.

app.js

//Opens form
$('#newListItem').on('click', function () {
    $('#newTaskForm,  #newListItem').fadeToggle('fast', 'linear');
});
//closes form
$('#cancel').on('click', function (e) {
    e.preventDefault();
    $('#newTaskForm,  #newListItem').fadeToggle('fast', 'linear');
});

#Step 3 Task Progression HTML ###Scaffold the lists

Before we make it possible to move our tasks from in progress to archived, we want create a space for them to exist in our HTML. We will do this in a very minimalist way in order to get things in a way they make sense.

All we really need to do is create divs with ULs within them that contain the IDs our jQuery will look for. Or in other words, let's make some hooks for our jQuery to find and manipulate!

Underneath our existing HTML in our index.html we should do this:

index.html

<div class="panel">
        In Progress
        <ul class="list-group" id="currentList"></ul>
</div>

<div class="panel">
        Archived
        <ul class="list-group" id="archivedList"></ul>
</div>

Let's also go into our CSS file and create a panel class

main.css

.panel {
	display: inline-block;
	width: 33%;
}

#Step 4 Task Progression jQuery ###Starting, Finishing, and Deleting Tasks

The next thing we want is to create a way for our tasks to be moved from new, to in progress, to archived, and eventually deleted.

If you remember, when we created our task constructor we took in the parameter for task, and we also created an ID that was automatically set to 'new'. In order to transition a task from 'new' to 'inProgress' all we really need to do is update the object's ID so that it says 'inProgress'.

First let's make a function that allows us to change the status of an item from 'new' to 'inProgress'.

app.js

$(document).on('click', '#item', function(e) {
	e.preventDefault();

});

From the beginning this function looks a little different than our other functions. For one, we call the document as the hook. Why are we doing that?

Remember, with jQuery the DOM doesn't really do anything. It's just there. That means all of the heavy lifting happens in jQuery. For this, and the next couple of functions, we will need to call the document so that as we create and manipulate html elements, the DOM realizes that they're there.

Another weird thing is e.preventDefault(); All this is saying is that we are removing the default properties of whatever HTML element we are clicking on. If we want an anchor tag so we can click on list items, but we don't want all of the baggage that comes with an anchor tag (like refreshing the page, or trying to take us to a new page) then this line of code will allow us to do that.

It's similar to when we use normalize.css to remove default HTML styles.

The last weird thing is that we are listing '#item' near our 'click' event. This is just so we can specify what we are affecting when we click.

Now let's set a variable called task so that we can access the 'this' keyword to pass it into another function.

We are also going to change it's ID to the string 'inProgress'.

app.js

$(document).on('click', '#item', function(e) {
	e.preventDefault();
    var task = this;		
    advanceTask(task);
    this.id = 'inProgress';
});

The last thing this function needs is the ability to move the actual list item. We do that by pulling all of the html around the item itself.

app.js

$(document).on('click', '#item', function(e) {
	e.preventDefault();
    var task = this;		
    advanceTask(task);
    this.id = 'inProgress';
    $('#currentList').append(this.outerHTML);

});

We can also move the items from 'inProgress' to 'archived' with a similar function:

app.js

$(document).on('click', '#inProgress', function (e) {
    e.preventDefault();
    var task = this;
    task.id = "archived";
    var changeIcon = task.outerHTML.replace('glyphicon-arrow-right', 'glyphicon-remove');
    advanceTask(task);
    $('#archivedList').append(changeIcon);
});

Finally, in a similar fashion we want to create a way to delete the items on the list. All we have to do is pass a task into the advanceTask function without a new id. You can study the advanceTask function we built to understand how it works!

app.js

$(document).on('click', '#archived', function (e) {
    e.preventDefault();
    var task = this;
    advanceTask(task);
});

A note on archiving A lot of times when writing software we don't necessarily want to delete things all out. Sometimes a user will accidently delete something, and if we are actually obliterating things. Doing what is called a soft delete is often a good thing to do.

Think of our archived ID like a soft delete. We could make it disappear to the user, but if there is a case where they made a mistake it's still accessible.

Perhaps it's not so important with a todolist, but it's good to start thinking about.

#Step 5 Local Storage ###Our Browsers Brain

The final step for the todo list is to save our list items on local storage. Local storage allows our app to access the browsers built in storage. We can save a limited amount of data in cool ways. This means if we close our browser our list items will still be there!

Jake is going to lecture about this