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And so we're starting to break out something
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2.34
that was pretty complicated into now two separate steps, where
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3.27
each step is relatively simple.
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3.07
But still in each step, we have to go about all of these steps
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3.08
in order to get what we want.
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5.11
So what might be a better way to do this?
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5.03
Well, rather than going through the steps, where we say, oh, hey,
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4.59
get me a new element called a list item and input button in a span,
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3.6
maybe we wanted just to write that all somewhat declaratively ourselves.
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4.03
And so we can actually do something called innerHTML,
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3.65
so say we created a list item.
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1.65
And maybe we want to take advantage of JavaScript's ability
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3.85
to do in-line string concatenation in order
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to create some HTML directly here.
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2.89
So we could do something like li.innerHTML,
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6.85
and we can start actually putting this directly in here.
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3.04
And so this will actually, in a more declarative manner, say,
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2.82
hey, I want an input, a button in the span,
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2.58
and just stick this in the innerHTML of that list item.
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3.87
And so it's starting to look somewhat like something
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we've seen before, right?
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1.62
It's starting to represent more of a React component.
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5.28
Do you guys see how that is starting to look a lot like what we were
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3.93
doing before, using React components?
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1.98
But let's stick with vanilla JavaScript still and take this a step further
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6.69
and actually store the to dos in memory.
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1.88
And so what have we been previously using to store to dos?
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3.68
Well, we've just been adding them to the DOM,
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3.18
and then using the DOM as a way to remember exactly what our to dos are.
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3.76
But what if we actually wanted to rather than storing it on the DOM,
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2.96
actually store that in JavaScript, in some sort of data
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2.34
structure in our JavaScripted memory?
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4.2
Well, that might be easier to do stuff like delete on.
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3.7
But how are we going to get that to the DOM?
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2.465
Well, we're going to actually have to write a method ourselves.
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2.625
And so maybe we have to dos stored in memory as an array.
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5.044
Maybe we have something called a render to do,
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which will actually render a single to do.
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2.08
And by render, I mean turn that to do, an object in memory,
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into actual HTML, something that the browser can display.
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3.816
And so that takes care of rendering a single to do,
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2.124
but how are we going to render that entire to do list?
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2.249
Well, maybe we want to clear the list and actually map over the to dos.
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7.711
So we do to dos dot map.
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1.23
What are we mapping?
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0.833
Well, let's actually render each of those to dos.
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2.537
And for each of the to dos that we rendered,
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2.14
go ahead and append that to the list.
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3.89
And so now we went from storing to dos in memory,
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3.32
creating this concept of rendering, where we turn a single JavaScript
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object into an actual thing that the browser can display.
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4.83
And then we have this concept called render, which
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actually renders all of our to dos.
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2.85
And so we go from what used to be a very imperative way of writing
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JavaScript, and going from having a single to do to appending that
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4.2
to the DOM.
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1.12
So now we're a more declarative way.
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1.88
We're declaring that a bunch of to dos may exist.
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2.94
We're declaring that, hey, here's a way to render a single to do
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3.78
and writing a way to turn that list into a full rendered page.
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7.654
And so now when we want to add a to do, rather
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1.916
than doing a bunch of DOM manipulation, maybe we actually
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3.12
want to just do something like a new to do and push that to the list.
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5.316
Well, once you push it to the list, now we have to manually say, hey,
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2.874
we updated the list.
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0.87
Let's go ahead and render that to the page.
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3.48
And so now if we're storing everything in memory,
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2.4
it becomes a lot easier to remove things.
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2.86
And so how are we going to remove the to dos?
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2.19
Well, we have to figure out exactly how to do the to dos,
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2.374
and this is just an implementation detail.
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1.826
But we can actually reset to dos to be a filtered list.
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2.67
So just filter them by excluding that to do that we didn't want to be included.
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7.65
And then we, again, since we changed everything,
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2.21
now we're going to have to go and manually kick off a render.
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3
And so now we're writing JavaScript in more of a declarative paradigm, more
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3.42
like what we saw in React earlier.
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2.52
But we're still implementing stuff like rendering and rendering a single to do
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4.8
and kicking off these things manually.
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2.61
And let's actually see how this looks if we were all to do it in React,
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3.75
where React actually handles a lot of the data rendering to the screen,
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4.17
using a library rather than stuff that we have to write manually.
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3.06
So let's actually do this from scratch.
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2.734
First let me save this.
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1.4
So let's go ahead and actually, from scratch, implement our to do list
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5.48
all in React.
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1.5
So of course, we're going to have to store stuff in state.
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2.67
So rather than having app be a function, what might we want to do instead?
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4.999
Have it be a class.
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0.791
And just like in the example I was showing earlier,
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2.124
we have a concept of rendering that app.
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2.002
React components actually do this automatically
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1.958
for you in this render method.
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2.28
And so let's go ahead and implement that rendering method.
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2.416
And so returning this.
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3.46
And now we have a blank to do list.
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7.475
So now we have a class called app.
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2.19
It's extending React component, which gives us what?
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4.5
It allows us to have state, and it gives us access
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2.49
to this thing called this dot set state in order to update the state.
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3.39