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And so we might do the
exact same thing with neck. | 1,107.58 | 3.11 |
And maybe we want to add
something like 19 frets. | 1,126.46 | 2.775 |
And you can see how this gets a little
bit annoying to write it, right? | 1,133.67 | 4.65 |
And maybe we do the
same thing with body, | 1,138.32 | 2.61 |
but we have some sort of for
each loop with the strings, | 1,140.93 | 9.39 |
and we pass in the tone that we want. | 1,150.32 | 3.881 |
And then we go ahead and create a
string and tune it to that tone. | 1,154.201 | 2.749 |
And then we go ahead and
add that to the body. | 1,165.604 | 1.916 |
And you see how this gets very
step-by-step, exactly what we | 1,177.93 | 4.371 |
want to do to create a guitar. | 1,182.301 | 1.249 |
And this is exactly what we've been
doing thus far for writing to the DOM. | 1,188.19 | 4.11 |
And so how might we do this
in a more declarative manner? | 1,195.265 | 2.375 |
Well, we would just
say, give me a guitar. | 1,201.38 | 3.995 |
Give me a string. | 1,208.58 | 1.57 |
Maybe I want it to be tuned to
the first note in the string. | 1,210.15 | 7.43 |
And maybe copy that a few times. | 1,221.382 | 1.333 |
And there we go. | 1,229.04 | 2.4 |
A better way to do this would be
rather than hard coding these, | 1,231.44 | 3.57 |
maybe we just do strings.map, and
for each note, we stick it in there. | 1,235.01 | 11.47 |
So it looks like there's
a little bug here. | 1,249.559 | 1.791 |
I used string even though I declared
the variable called strings. | 1,251.35 | 5.97 |
So if we map over the
array called strings, | 1,257.32 | 2.73 |
and for each note return a
string where the note is note, | 1,260.05 | 3.45 |
then we have declaratively
written a guitar. | 1,263.5 | 3.386 |
Does this make sense? | 1,266.886 | 0.874 |
So a great thing about react
is that the way that you code | 1,275.58 | 2.76 |
is in a very, very declarative manner. | 1,278.34 | 3.9 |
The browser APIs aren't
super fun to work with. | 1,282.24 | 2.43 |
You get to work with them a bit
in project zero, but react just | 1,284.67 | 3.96 |
allows us to write exactly what we want. | 1,288.63 | 1.68 |
And the library will actually take
care of the DOM manipulation for us. | 1,290.31 | 3.92 |
And so what does that really look like? | 1,294.23 | 1.75 |
So say we wanted to create a slide here. | 1,303.97 | 3.825 |
Say we wanted to use the
native DOM manipulation | 1,307.795 | 4.685 |
API in order to create the slide here. | 1,312.48 | 2.41 |
So we might have a slide
element that we created | 1,314.89 | 3.14 |
and say we wanted to add a H1 to that. | 1,318.03 | 2.66 |
Add a title to it. | 1,320.69 | 0.76 |
How might we do it? | 1,321.45 | 1.26 |
Well, we'd have to do something like
const title = document.createElement. | 1,322.71 | 4.514 |
Get an H1. | 1,331.18 | 2.43 |
And then start adding to that. | 1,333.61 | 1.25 |
We can do title.innerHTML
is equal to the SLIDE.title. | 1,334.86 | 5.23 |
And you see how this starts getting
to like what we've been doing earlier, | 1,344.19 | 3.36 |
where you say exactly what you want,
but it might take you a long time to do. | 1,347.55 | 5.501 |
So in react land, this
is actually a lot easier. | 1,353.051 | 1.999 |
So how might we do this if we were
doing this completely declaratively? | 1,358.84 | 4.4 |
Well, we just say exactly what we want. | 1,363.24 | 7.57 |
We want a slide. | 1,370.81 | 2.09 |
Maybe it has a title, where the
title is equal to the slide's title. | 1,372.9 | 5.565 |
Maybe we have some bullets. | 1,381.27 | 2.619 |
Or we can just map through the
bullets that we have up there. | 1,383.889 | 2.541 |
We can do SLIDE.bullets.map. | 1,386.43 | 2.01 |
And we can say for every bullet,
just give me a list item. | 1,392.41 | 5.75 |
And maybe we should wrap those
list items in unordered list. | 1,409.451 | 2.499 |
And maybe instead of using
this, we can do an H1 here. | 1,416.17 | 2.25 |
So see how this is a
lot more declarative? | 1,431.07 | 2.32 |
Makes sense, right? | 1,441.73 | 1.17 |
It just makes sense. | 1,442.9 | 1.51 |
It's easier to read, and
it's easier to maintain. | 1,444.41 | 3.02 |
So another great thing about react
is it's very easily componentized. | 1,450.552 | 4.475 |
What do I mean by componentized? | 1,455.027 | 1.333 |
Well, it's a process by which you break
a very complex problem into a bunch | 1,456.36 | 3.48 |
of different, discrete components. | 1,459.84 | 2.746 |
You can reuse these components,
which is great for consistency. | 1,462.586 | 2.624 |
So say you had a bunch
of slides, and you wanted | 1,465.21 | 2.31 |
to just change how every title looked. | 1,467.52 | 2.735 |
Well, if you did this using
native DOM manipulation, | 1,470.255 | 2.995 |
that might be a bunch of different
lines of code that you have to change. | 1,473.25 | 3.41 |
But if you did this
using React components, | 1,476.66 | 2.787 |
it might just be one line
that you have to change, | 1,479.447 | 2.083 |
and then it's applied to every
single slide that you have. | 1,481.53 | 2.922 |
It's also great for iteration
speed, because then you | 1,484.452 | 2.208 |
can just reuse the
components over and over, | 1,486.66 | 1.833 |
rather than having to cut and
paste code all over the place. | 1,488.493 | 3.438 |
Another great thing
about these components | 1,491.931 | 1.749 |
is that React's declarative nature makes
it very easy to customize components. | 1,493.68 | 4.74 |
So say we had the last three slides
and wanted to write them in HTML. | 1,498.42 | 3.61 |
It might look like
something like this, where | 1,505.065 | 1.875 |
you have a div, which represents
a slide where the titles react. | 1,506.94 | 5.72 |
You notice these are the same
three bullets as previously. | 1,512.66 | 2.8 |
We have the declarative slide, where
we have the same bullets as previously. | 1,515.46 | 5.015 |
And say we wanted to change this. | 1,520.475 | 1.375 |
Say we wanted to make all of the
titles have a slightly different style. | 1,521.85 | 5.28 |
Well, how might we do that? | 1,527.13 | 1.71 |
Well, we'd have to edit this line. | 1,528.84 | 1.77 |
We'd have to go edit this line. | 1,530.61 | 1.86 |
Maybe down there, there's another
title that we have to change. | 1,532.47 | 2.73 |
Or what if we wanted to even change the
structure of how we represent bullets? | 1,535.2 | 4.47 |
Maybe rather than using
an unordered list, | 1,539.67 | 2.72 |
we might use an unordered list with
a div that wraps the list items. | 1,542.39 | 4.43 |
Well, in order to do that, that would
be a lot of code you have to change. | 1,546.82 | 3.83 |
But imagine that we had broken this up
into a bunch of different components. | 1,550.65 | 3.66 |
Where might it make
sense to break it up? | 1,554.31 | 2.99 |
Well, you see us repeating code
that looks pretty much the same | 1,557.3 | 4.042 |
over here, right? | 1,561.342 | 0.708 |
So maybe that should be broken
up into a separate component. | 1,562.05 | 3.3 |
So how might we go about doing that? | 1,565.35 | 1.65 |
Well, first we have to extract the
information, and so in this array here, | 1,571.05 | 4.61 |
we have the slides where
I've basically just ripped | 1,575.66 | 3.27 |