text stringlengths 1 81 | start float64 0 10.1k | duration float64 0 24.9 |
|---|---|---|
And so we're starting
to break out something | 3,544.19 | 2.34 |
that was pretty complicated into
now two separate steps, where | 3,546.53 | 3.27 |
each step is relatively simple. | 3,549.8 | 3.07 |
But still in each step, we have
to go about all of these steps | 3,552.87 | 3.08 |
in order to get what we want. | 3,555.95 | 5.11 |
So what might be a
better way to do this? | 3,561.06 | 5.03 |
Well, rather than going through
the steps, where we say, oh, hey, | 3,566.09 | 4.59 |
get me a new element called a list
item and input button in a span, | 3,570.68 | 3.6 |
maybe we wanted just to write that
all somewhat declaratively ourselves. | 3,574.28 | 4.03 |
And so we can actually do
something called innerHTML, | 3,578.31 | 3.65 |
so say we created a list item. | 3,581.96 | 1.65 |
And maybe we want to take
advantage of JavaScript's ability | 3,593.35 | 3.85 |
to do in-line string
concatenation in order | 3,597.2 | 3.99 |
to create some HTML directly here. | 3,601.19 | 2.89 |
So we could do something
like li.innerHTML, | 3,604.08 | 6.85 |
and we can start actually
putting this directly in here. | 3,610.93 | 3.04 |
And so this will actually, in
a more declarative manner, say, | 3,627.31 | 2.82 |
hey, I want an input,
a button in the span, | 3,630.13 | 2.58 |
and just stick this in the
innerHTML of that list item. | 3,632.71 | 3.87 |
And so it's starting to
look somewhat like something | 3,636.58 | 2.91 |
we've seen before, right? | 3,639.49 | 1.62 |
It's starting to represent
more of a React component. | 3,641.11 | 5.28 |
Do you guys see how that is starting
to look a lot like what we were | 3,646.39 | 3.93 |
doing before, using React components? | 3,650.32 | 1.98 |
But let's stick with vanilla JavaScript
still and take this a step further | 3,656.62 | 6.69 |
and actually store the to dos in memory. | 3,663.31 | 1.88 |
And so what have we been
previously using to store to dos? | 3,665.19 | 3.68 |
Well, we've just been
adding them to the DOM, | 3,668.87 | 3.18 |
and then using the DOM as a way to
remember exactly what our to dos are. | 3,672.05 | 3.76 |
But what if we actually wanted to
rather than storing it on the DOM, | 3,675.81 | 2.96 |
actually store that in
JavaScript, in some sort of data | 3,678.77 | 2.34 |
structure in our JavaScripted memory? | 3,681.11 | 4.2 |
Well, that might be easier
to do stuff like delete on. | 3,685.31 | 3.7 |
But how are we going
to get that to the DOM? | 3,689.01 | 2.465 |
Well, we're going to actually
have to write a method ourselves. | 3,691.475 | 2.625 |
And so maybe we have to dos
stored in memory as an array. | 3,694.1 | 5.044 |
Maybe we have something
called a render to do, | 3,699.144 | 1.916 |
which will actually
render a single to do. | 3,701.06 | 2.08 |
And by render, I mean turn that
to do, an object in memory, | 3,703.14 | 4.13 |
into actual HTML, something
that the browser can display. | 3,707.27 | 3.816 |
And so that takes care of
rendering a single to do, | 3,711.086 | 2.124 |
but how are we going to
render that entire to do list? | 3,713.21 | 2.249 |
Well, maybe we want to clear the list
and actually map over the to dos. | 3,715.459 | 7.711 |
So we do to dos dot map. | 3,723.17 | 1.23 |
What are we mapping? | 3,724.4 | 0.833 |
Well, let's actually render
each of those to dos. | 3,725.233 | 2.537 |
And for each of the to
dos that we rendered, | 3,727.77 | 2.14 |
go ahead and append that to the list. | 3,729.91 | 3.89 |
And so now we went from
storing to dos in memory, | 3,733.8 | 3.32 |
creating this concept of rendering,
where we turn a single JavaScript | 3,737.12 | 3.99 |
object into an actual thing
that the browser can display. | 3,741.11 | 4.83 |
And then we have this
concept called render, which | 3,745.94 | 2.22 |
actually renders all of our to dos. | 3,748.16 | 2.85 |
And so we go from what used to be
a very imperative way of writing | 3,751.01 | 2.88 |
JavaScript, and going from having
a single to do to appending that | 3,753.89 | 4.2 |
to the DOM. | 3,758.09 | 1.12 |
So now we're a more declarative way. | 3,759.21 | 1.88 |
We're declaring that a
bunch of to dos may exist. | 3,761.09 | 2.94 |
We're declaring that, hey, here's
a way to render a single to do | 3,764.03 | 3.78 |
and writing a way to turn that
list into a full rendered page. | 3,767.81 | 7.654 |
And so now when we want
to add a to do, rather | 3,775.464 | 1.916 |
than doing a bunch of DOM
manipulation, maybe we actually | 3,777.38 | 3.12 |
want to just do something like a
new to do and push that to the list. | 3,780.5 | 5.316 |
Well, once you push it to the list,
now we have to manually say, hey, | 3,785.816 | 2.874 |
we updated the list. | 3,788.69 | 0.87 |
Let's go ahead and
render that to the page. | 3,789.56 | 3.48 |
And so now if we're storing
everything in memory, | 3,793.04 | 2.4 |
it becomes a lot easier
to remove things. | 3,795.44 | 2.86 |
And so how are we going
to remove the to dos? | 3,798.3 | 2.19 |
Well, we have to figure out
exactly how to do the to dos, | 3,800.49 | 2.374 |
and this is just an
implementation detail. | 3,802.864 | 1.826 |
But we can actually reset to
dos to be a filtered list. | 3,804.69 | 2.67 |
So just filter them by excluding that to
do that we didn't want to be included. | 3,807.36 | 7.65 |
And then we, again, since
we changed everything, | 3,815.01 | 2.21 |
now we're going to have to go
and manually kick off a render. | 3,817.22 | 3 |
And so now we're writing JavaScript in
more of a declarative paradigm, more | 3,820.22 | 3.42 |
like what we saw in React earlier. | 3,823.64 | 2.52 |
But we're still implementing stuff like
rendering and rendering a single to do | 3,826.16 | 4.8 |
and kicking off these things manually. | 3,830.96 | 2.61 |
And let's actually see how this looks
if we were all to do it in React, | 3,833.57 | 3.75 |
where React actually handles a lot
of the data rendering to the screen, | 3,837.32 | 4.17 |
using a library rather than stuff
that we have to write manually. | 3,841.49 | 3.06 |
So let's actually do this from scratch. | 3,848.036 | 2.734 |
First let me save this. | 3,850.77 | 1.4 |
So let's go ahead and actually, from
scratch, implement our to do list | 3,873.79 | 5.48 |
all in React. | 3,879.27 | 1.5 |
So of course, we're going to
have to store stuff in state. | 3,880.77 | 2.67 |
So rather than having app be a function,
what might we want to do instead? | 3,883.44 | 4.999 |
Have it be a class. | 3,888.439 | 0.791 |
And just like in the example
I was showing earlier, | 3,895.896 | 2.124 |
we have a concept of rendering that app. | 3,898.02 | 2.002 |
React components actually
do this automatically | 3,900.022 | 1.958 |
for you in this render method. | 3,901.98 | 2.28 |
And so let's go ahead and
implement that rendering method. | 3,918.054 | 2.416 |
And so returning this. | 3,932.98 | 3.46 |
And now we have a blank to do list. | 3,942.745 | 7.475 |
So now we have a class called app. | 3,950.22 | 2.19 |
It's extending React
component, which gives us what? | 3,952.41 | 4.5 |
It allows us to have state,
and it gives us access | 3,956.91 | 2.49 |
to this thing called this dot set
state in order to update the state. | 3,959.4 | 3.39 |
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