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:END:
Welcome to /Foundations of High-Performance React Applications/ where
we build our own simplified version of React. We will use our React to
we build our own simplified version of React. We’ll use our React to
gain an understanding of the real React and how to build
high-performance applications with it.
This book is based on the first chapter of the book /High-Performance
React/. If you enjoy this book and you want to learn more practical
ways to utilize the foundations we will learn here and get a more
detailed blue-print for creating high performance React applications,
ways to utilize the foundations we’ll learn here and get a more
detailed blueprint for creating high performance React applications,
then be sure to check out /High-Performance React/.
This book is not intended to be an introduction to React or
JavaScript. While it might be useful to beginners, this book assumes
familiarity with both JavaScript and React.
And while this book only specifically addresses React-DOM the
And while this book only specifically addresses React-DOM, the
foundations apply equally to React-Native and other React
implementations because they are all based on the same core React
library and algorithms.
For the code in this book, the goal is to be clear and simple; to best
communicate the algorithms we will be exploring. It is not intended to
be used in production but it is functional and you will likely find it
useful to follow along by also writing the code yourself. It will help
The code in this book is clear and simple so as to best
communicate the algorithms we’ll be exploring. It is not intended to
be used in production, but it is functional. I think you’ll likely find it
useful to follow along by writing the code yourself. It will help
you better understand how it works, and even more critically, it will
allow you to play with it and test how the algorithms work with your
own examples.
Even if you don't write out the code yourself and instead treat this
book more as a novel you read through and then move on, I believe the
fundamentals should still stick with you and provide value in your
Even if you don't write out the code yourself and,instead, read through this
book more like a novel, I believe the
fundamentals will still stick with you and provide value in your
React programs-to-come.
I'm very excited to take you on this journey with me and now it's time
to learn what lays at the very foundation of React.
I'm very excited to take you on this journey with me and, so, now it's time
to learn what lies at the very foundation of React.
* Acknowledgments
:PROPERTIES:
:EXPORT_FILE_NAME: manuscript/acknowledgments.markua
:END:
First, I'd like to thank my partner Laura, for always supporting me in
whatever endeavors I embark upon even if they're new, challenging, or
scary. This book, nor my work with React, would have taken place if it
First, I'd like to thank my partner Laura for always supporting me in
whatever endeavors I embark upon, whether they're new, challenging, or
scary. This book and my work with React wouldn’t have taken place if it
weren't for her support and strength.
Second, I would like to thank my friend, Timothy Licata, for providing
Second, I would like to thank my friend Timothy Licata for providing
invaluable feedback on earlier versions and always pushing me to
explore new ways of using Emacs, such as writing this book.
And last, I would like to thank the wider JavaScript and React
community for providing many years of work to build upon and
community for providing many years of work to build upon,
specifically Rodrigo Pombo's "Build Your Own React" for being the
inspiration for a lot of this book's content.
* Introduction :mainmatter:
@@ -82,40 +82,39 @@ inspiration for a lot of this book's content.
:EXPORT_FILE_NAME: manuscript/introduction.markua
:END:
Baking bread. When I first began to learn how to bake bread the recipe
told me what to do. It listed some ingredients and told me how to
combine them and prescribed times of rest. It gave me an oven
When I first began to learn how to bake bread, a recipe
told me what to do. It listed some ingredients, told me how to
combine them, and prescribed times of rest. It gave me an oven
temperature and a period of wait. It gave me mediocre bread of wildly
varying quality. I tried different recipes but the result was always
varying quality. I tried different recipes, but the result was always
the same.
Understanding: that's what I was missing. The bread I make is now
consistently good. The recipes I use are simpler and only give ratios
and general recommendations for rests and waits. So why does the bread
turn out better?
and general recommendations for rests and waits. So, why does the bread
now turn out better?
Before baking is finished bread is a living organism. The way it grows
and develops and flavors depend on what you feed it and how you feed
it and massage it, care for it. If you have it grow and ferment at a
higher temperature and more yeast it overdevelops producing too much
alcohol. If you give it too much time, acidity will take over the
flavor. The recipes I used initially were missing a critical
ingredient: the rising temperature.
Before it is baked, bread is a living organism. So, the way it grows,
develops, and flavors depends on what you feed it, how you feed it,
how you massage it, and how you care for it. If you have it grow and
ferment with more yeast at a higher temperature, it
overdevelops, producing too much alcohol. If you give it too much time,
acidity will take over the flavor. The recipes I used initially were
missing a critical ingredient: the rising temperature.
But unlike a lot of ingredients: temperature is hard to control for
the home cook. So the recipe can't just tell you exactly what
temperature to grow the bread at. My initial recipes just silently
made assumptions for the temperature, which rarely turn out to be
true. This means that the only way to consistently make good bread is
to have an understanding of how bread develops so that you can adjust
the other ingredients to complement the temperature. Now the bread can
tell me what to do.
But unlike other ingredients, temperature is hard for the home cook to
control. And recipes don’t say exactly at which temperature to grow
the bread. My initial recipes just silently made assumptions about the
temperature, which rarely worked. This means the only way to
consistently make good bread is to have an understanding of how bread
develops so that you can adjust the other ingredients to complement
the temperature. Now the bread can tell me what to do.
While React isn't technically a living organism that can tell us what
to do, it is, in its whole, a complex, abstract entity. We could learn
basic recipes for how to write high-performance React code but they
wouldn't apply in all cases, and as React and things under it change
our recipes would fall out-of-date. So like the bread, to produce
basic recipes for how to write high-performance React code, but they
wouldn't apply in all cases. And as React and things under it change,
our recipes would fall out-of-date. So, like bread, to produce
consistently good results we need to understand how React does what it
does.
@@ -139,19 +138,19 @@ differences it updates the browser's DOM to match its internal tree.
But what does that actually look like? If your app is janky does that
explanation point you towards what is wrong? No. It might make you
wonder if maybe it is too expensive to re-render the tree or if maybe
the diffing React does is slow but you won't really know. When I was
the diffing React does is slow, but you won't really know. When I was
initially testing out different bread recipes I had guesses at why it
wasn't working but I didn't really figure it out until I had a deeper
wasn't working, but I didn't really figure it out until I had a deeper
understanding of how making bread worked. It's time we build up our
understanding of how React works so that we can start to answer our
questions with solid answers.
React is centered around the ~render~ method. The ~render~ method is
React is centered on the ~render~ method. The ~render~ method is
what walks our trees, diffs them with the browser's DOM tree, and
updates the DOM as needed. But before we can look at the ~render~
method we have to understand its input. The input comes from
~createElement~. While ~createElement~ itself is unlikely to be a
bottleneck it's good to understand how it works so that we can have a
bottleneck, it's good to understand how it works so that we can have a
complete picture of the entire process. The more black-boxes we have
in our mental model the harder it will be for us to diagnose
performance problems.
@@ -165,14 +164,14 @@ performance problems.
not familiar to us since we usually work in JSX, which is the last
element of the chain in this puzzle and the first step in solving
it. While not strictly a part of React, it is almost universally used
with it. And if we understand it then ~createElement~ will be less of
a mystery since we will be able to connect all the dots.
with it. And if we understand it, ~createElement~ will then be less of
a mystery since we’ll be able to connect all the dots.
JSX is not valid HTML or JavaScript but its own language compiled by a
compiler, like Babel. The output of that compilation is valid
JavaScript that represents the original markup.
Before JSX or similar compilers, the normal way of injecting HTML into
Before JSX or similar compilers, the typical way of injecting HTML into
the DOM was via directly utilizing the browser's DOM APIs or by
setting ~innerHTML~. This was very cumbersome. The code's structure
did not match the structure of the HTML that it output which made it
@@ -180,12 +179,12 @@ hard to quickly understand what the output of a piece of code would
be. So naturally programmers have been endlessly searching for better
ways to mix HTML with JavaScript.
And this brings us to JSX. It is nothing new; nothing
And this brings us to JSX. It is nothing new, nothing
complicated. Forms of it have been made and used long before React
adopted it. Now let's see if we can discover JSX for ourselves.
To start with, we need to create a data-structure -- let's call it
JavaScript Markup (JSM) -- that both represents a DOM tree and can
To start with, we need to create a data-structure – let's call it
JavaScript Markup (JSM) – that both represents a DOM tree and can
also be used to insert one into the browser's DOM. And to do that we
need to understand what a tree of DOM nodes is constructed of. What
parts do you see here?
@@ -227,15 +226,15 @@ This is what I'm thinking:
As you can see, we have a clear mapping from our notation, JSM, to the
original HTML. Our tree is made up of three element arrays. The first
item in the array is the tag, the second is an object containing the
tag's properties, and the third is an array of its children; which are
tag's properties, and the third is an array of its children which are
all made up of the same three element arrays.
The truth is though, if you stare at it long enough, although the
The truth is, if you stare at it long enough, although the
mapping is clear, how much fun would it be to read and write that on a
consistent basis? I can assure you, it is rather not fun. But it has
consistent basis? I can assure you, it is not fun. But it has
the advantage of being easy to insert into the DOM. All you need to do
is write a simple recursive function that ingests our data structure
and updates the DOM accordingly. We will get back to that.
and updates the DOM accordingly. We’ll get back to that.
So now we have a way to represent a tree of nodes and we
(theoretically) have a way to get those nodes into the DOM. But if we
@@ -246,7 +245,7 @@ And this is where our object of study enters the scene. JSX is just a
notation that a compiler takes as input and outputs in its place a
tree of nodes nearly identical to the notation we came up with! And if
you look back to our notation you can see that you can easily embed
arbitrary JavaScript expressions wherever you want in a node. As you
in a node arbitrary JavaScript expressions wherever you want. As you
may have realized, that's exactly what the JSX compiler does when it
sees curly braces!
@@ -270,12 +269,12 @@ React.createElement(
);
#+END_SRC
As you can see, it is very similar to our JSM data-structure and for
the purposes of this book we will use JSM, as it's a bit easier to
As you can see, it is very similar to our JSM data-structure and, for
the purposes of this book, we’ll use JSM, as it's a bit easier to
work with. A JSX compiler also does some validation and escapes input
to prevent cross-site scripting attacks. In practice though, it would
behave the same in our areas of study and we will keep things simple
by leaving those aspects of the JSX compiler out.
behave the same in our areas of study and we’ll keep things simple
by leaving out those aspects of the JSX compiler.
So now that we've worked through JSX we're ready to tackle
~createElement~, the next item on our way to building our own React.
@@ -304,10 +303,10 @@ React expects nodes defined as JavaScript objects that look like this:
}
#+END_SRC
That is: an object with two properties: ~type~ and ~props~. The
That is, an object with two properties: ~type~ and ~props~. The
~props~ property contains all the properties of the node. The node's
~children~ are also considered part of its properties. The full
version of React's ~createElement~ includes more properties but they
version of React's ~createElement~ includes more properties, but they
are not relevant to our study here.
#+BEGIN_SRC javascript
@@ -340,7 +339,7 @@ elements. The first part tests whether ~node~ is a complex node
(specified by an array) and then generates an ~element~ object based
on the input node. It recursively calls ~createElement~ to generate an
array of children elements. If the node is not complex then we
generate an element of type 'TEXT' which we use for all primitives
generate an element of type 'TEXT' which we use for all primitives,
like strings and numbers. We call the output of ~createElement~ a tree
of ~elements~ (surprise).
@@ -353,9 +352,8 @@ process of rendering our tree to the DOM!
:END:
There are now only two major puzzles remaining in our quest for our
own React. The next piece is: ~render~. How do we go from our JSM tree
of nodes, to actually displaying something on screen? To do that we
will explore the ~render~ method.
own React. The next piece is ~render~. How do we go from our JSM tree
of nodes to actually displaying something on screen? We do this by exploring the ~render~ method.
The signature for our ~render~ method should be familiar to you:
@@ -375,16 +373,16 @@ function render(element, container) {
#+END_SRC
Our DOM element is created first. Then we set the properties, render
children elements, and finally append the whole tree to the
the children elements, and finally append the whole tree to the
container.
Now that we have an idea of what to build we will work on expanding
Now that we have an idea of what to build we’ll work on expanding
the pseudocode until we have our own fully functional ~render~ method
using the same general algorithm React uses. In our first pass we will
by using the same general algorithm that React uses. In our first pass we’ll
focus on the initial render and ignore reconciliation.
#+begin_note
Reconciliation is basically React's "diffing" algorithm. We will be
Reconciliation is basically React's "diffing" algorithm. We’ll be
exploring it after we work out the initial render.
#+end_note
@@ -428,7 +426,7 @@ reconciliation.
:PROPERTIES:
:EXPORT_FILE_NAME: manuscript/reconciliation.markua
:END:
A tale of two trees. These are the two trees that people most often
This is a tale of two trees, the two trees that people most often
talk about when talking about React's "secret sauce": the virtual DOM
and the browser's DOM tree. This idea is what originally set React
apart. React's reconciliation is what allows you to program
@@ -444,48 +442,48 @@ diffing" algorithm.
Unfortunately, those researching tree diffing in Computer Science have
not yet produced a generic algorithm with sufficient performance for
use in something like React; as the current best algorithm still [[https://grfia.dlsi.ua.es/ml/algorithms/references/editsurvey_bille.pdf][runs
use in something like React, as the current best algorithm still [[https://grfia.dlsi.ua.es/ml/algorithms/references/editsurvey_bille.pdf][runs
in O(n^3)]].
Since an O(n^3) algorithm isn't going to cut it in the real-world, the
creators of React instead use a set of heuristics to determine what
parts of the tree have changed. Understanding how the React tree
diffing algorithm works in general and the heuristics currently in use
can help immensely in detecting and fixing React performance
parts of the tree have changed. Understanding the heuristics currently
in use and how the React tree diffing algorithm works in general can
help immensely in detecting and fixing React performance
bottlenecks. And beyond that it can help one's understanding of some
of React's quirks and usage. Even though this algorithm is internal to
React and can be changed anytime its details have leaked out in some
ways and are overall unlikely to change in major ways without larger
React and can be changed anytime, its details have leaked out in some
ways and, overall, are unlikely to change in major ways without larger
changes to React itself.
According to the [[https://reactjs.org/docs/reconciliation.html][React documentation]] their diffing algorithm is O(n)
and based on two major components:
According to the [[https://reactjs.org/docs/reconciliation.html][React documentation]] the diffing algorithm is O(n)
and is based on two major components:
- Elements of differing types will yield different trees
- You can hint at tree changes with the ~key~ prop.
In this section we will focus on the first part: differing types.
In this section we’ll focus on the first part: differing types.
#+begin_note
In this book we won't be covering keys in depth but you will see why
In this book we won't be covering keys in depth, but you’ll see why
it's very important to follow the guidance from React's documentation
that keys be: stable, predictable, and unique.
that keys are stable, predictable, and unique.
#+end_note
The approach we will take here is to integrate the heuristics that
The approach we’ll take here is to integrate the heuristics that
React uses into our ~render~ method. Our implementation will be very
similar to how React itself does it and we will discuss React's actual
similar to how React itself does it and we’ll discuss React's actual
implementation later when we talk about Fibers.
Before we get into the code changes that implement the heuristics it
Before we get into the code changes that implement the heuristics, it
is important to remember that React /only/ looks at an element's type,
existence, and key. It does not do any other diffing. It does not diff
props. It does not diff sub-trees of modified parents.
While keeping that in mind, here is an overview of the algorithm we
will be implementing in the ~render~ method. ~element~ is the element
from the current tree and ~prevElement~ is the corresponding element
in the tree from the previous render.
While keeping that in mind, here is an overview of the algorithm we’ll
be implementing in the ~render~ method. ~element~ is the element from
the current tree and ~prevElement~ is the corresponding element in the
tree from the previous render.
#+BEGIN_SRC javascript
if (!element && prevElement)
@@ -505,21 +503,21 @@ still be invoked.
Now, to get started with our render method we must make some
modifications to our previous render method. First, we need to be able
to store and retrieve the previous render tree. Then we need to add
code to compare parts of the tree to decide if we can re-use DOM
to store and retrieve the previous render tree. Then, we need to add
code to compare parts of the tree to decide if we can reuse DOM
elements from the previous render tree. And last, we need to return a
tree of elements that can be used in the next render as a comparison
and to reference the DOM elements that we create. These new element
objects will have the same structure as our current elements but we
will add two new properties: ~domElement~ and ~parent~. ~domElement~
is the DOM element associated with our synthetic element and ~parent~
is a reference to the parent DOM element.
objects will have the same structure as our current elements but we’ll
add two new properties: ~domElement~ and ~parent~. ~domElement~ is the
DOM element associated with our synthetic element and ~parent~ is a
reference to the parent DOM element.
Here we begin by adding a global object that will store our last render
tree, keyed by the ~container~. ~container~ refers to the browser's
DOM element that will be the parent for all of the React derived DOM
elements. This parent DOM element can only be used to render one tree
of elements at a time so it works well to use as a key for
of elements at a time, so it works well to use it as a key for
~renderTrees~.
#+BEGIN_SRC javascript
@@ -537,16 +535,16 @@ As you can see, the change we made is to move the core of our
algorithm into a new function called ~render_internal~ and pass in the
result of our last render to ~render_internal~.
Now that we have stored our last render tree we can go ahead and
Now that we have stored our last render tree, we can go ahead and
update our render method with the heuristics for reusing the DOM
elements. We name it ~render_internal~ because it is what controls the
rendering but takes an additional argument now: the
rendering, but it now takes an additional argument: the
~prevElement~. ~prevElement~ is a reference to the corresponding
~element~ from the previous render and contains a reference to its
associated DOM element and parent DOM element. If it's the first
render or if we are rendering a new node or branch of the tree then
render or if we are rendering a new node or branch of the tree, then
~prevElement~ will be ~undefined~. If, however, ~element~ is
~undefined~ and ~prevElement~ is defined then we know we need to
~undefined~ and ~prevElement~ is defined, then we know we need to
delete a node that previously existed.
#+BEGIN_SRC javascript
@@ -589,11 +587,11 @@ render its children is when we are deleting an existing DOM
element. We use this observation to group the calls for ~setDOMProps~
and ~renderChildren~. Choosing when to append a new DOM element to the
container is also part of the heuristics. If we can reuse an existing
DOM element then we do, but if the element type has changed or if
there was no corresponding existing DOM element then and only then do
DOM element, then we do this, but if the element type has changed or if
there was no corresponding existing DOM element, then, and only then, do
we append a new DOM element. This ensures the actual DOM tree isn't
being replaced every time we render, only the elements that change are
replaced.
being replaced.
In the real React, when a new DOM element is appended to the DOM tree,
React would invoke ~componentDidMount~ or schedule ~useEffect~.
@@ -612,12 +610,12 @@ function removeDOMElement(prevElement) {
}
#+END_SRC
In creating a new DOM element we just need to branch if we are
In creating a new DOM element, we just need to branch if we are
creating a text element since the browser API differs slightly. We
also populate the text element's value as the API requires the first
argument to be specified even though later on when we set props we
will set it again. This is where React would invoke
~componentWillMount~ or schedule ~useEffect~.
also populate the text element's value, as the API requires the first
argument to be specified even though later on when we set props we’ll
set it again. This is where React would invoke ~componentWillMount~ or
schedule ~useEffect~.
#+BEGIN_SRC javascript
function createDOMElement(element) {
@@ -656,7 +654,7 @@ need to be updated or removed.
#+begin_warning
This algorithm for setting props does not correctly handle events,
which must be treated specially. For this exercise that detail is not
which must be treated specially. For this exercise, that detail is not
important and we leave it out for simplicity.
#+end_warning
@@ -665,7 +663,7 @@ elements that are no longer being used. This would happen when the
number of children is decreased. The second loop starts at the first
child and then iterates through all of the children of the parent
element, calling ~render_internal~ on each child. When
~render_internal~ is called the corresponding previous element in that
~render_internal~ is called, the corresponding previous element in that
position is passed to ~render_internal~, or ~undefined~ if there is no
corresponding element, like when the list of children has grown.
@@ -692,7 +690,7 @@ It's very important to understand the algorithm used here because this
is essentially what happens in React when incorrect keys are used,
like using a list index for a key. And this is why keys are so
critical to high performance (and correct) React code. For example, in
our algorithm here, if you removed an item from the front of the list
our algorithm here, if you removed an item from the front of the list,
you may cause every element in the list to be created anew in the DOM
if the types no longer match up. In this book we won't be
incorporating keys, but it's actually only a minor difference in
@@ -700,7 +698,7 @@ determining which ~child~ gets paired with which
~prevChild~. Otherwise this is effectively the same algorithm React
uses when rendering lists of children.
#+CAPTION: Example of ~renderChildren~ 2nd loop when the 1st element has been removed. In this case the trees for all of the children will be torn down and rebuilt.
#+CAPTION: Example of ~renderChildren~ 2nd loop when the 1st element has been removed. In this case, the trees for all of the children will be torn down and rebuilt.
| i | child Type | prevChild Type |
|---+------------+----------------|
| 0 | span | div |
@@ -709,8 +707,8 @@ uses when rendering lists of children.
There are a few things to note here. First, it is important to pay
attention to when React will be removing a DOM element from the tree
and adding a new one as this is when the related lifecycle events or
hooks are invoked. And invoking those lifecycle methods or hooks, and
and adding a new one, as this is when the related lifecycle events, or
hooks, are invoked. And invoking those lifecycle methods, or hooks, and
the whole process of tearing down and building up a component is
expensive. So again, if you use a bad key, like the algorithm here
simulates, you'll be hitting a major performance bottleneck since
@@ -724,24 +722,24 @@ tearing down and rebuilding the trees of child components.
The actual React implementation used to look very similar to what
we've built so far, but with React 16 this has changed dramatically
with the introduction of Fibers. Fibers are a name that React gives to
with the introduction of Fibers. Fibers is a name that React gives to
discrete units of work during the render process. And the React
reconciliation algorithm was changed to be based on small units of
work instead of one large, potentially long-running call to
~render~. This means that React is now able to process just part of
the render phase, pause to let the browser take care of other things,
and resume again. This is the underlying change the enables the
experimental Concurrent Mode as well as running most hooks without
and resume again. This is the underlying change that enables the
experimental Concurrent Mode as well as runs most hooks without
blocking the render.
But even with such a large change, the underlying algorithms for
deciding how and when to render components is the same. And when not
running in Concurrent Mode the effect is still the same as React does
the render phase in one block still. So using a simplified
But even with such a large change, the underlying algorithms that
decide how and when to render components are the same. And, when not
running in Concurrent Mode, the effect is still the same, as React
still does the render phase in one block. So, using a simplified
interpretation that doesn't include all the complexities of breaking
up the process in to chunks enables us to see more clearly how the
process as a whole works. At this point bottlenecks are much more
likely to occur from the underlying algorithms and not from the Fiber
process works as a whole. At this point, bottlenecks are much more
likely to occur from the underlying algorithms and not from the Fibers
specific details.
* Putting it all together
@@ -749,7 +747,7 @@ specific details.
:EXPORT_FILE_NAME: manuscript/putting-it-all-together.markua
:END:
Now that we've explored how React renders your components it's time to
Now that we've explored how React renders your components, it's time to
finally create some components and use them!
#+BEGIN_SRC javascript
@@ -771,7 +769,7 @@ render(createElement(App()),
document.getElementById('root'));
#+END_SRC
We are creating two components, that output JSM, as we defined it
We are creating two components that output JSM, as we defined it
earlier. We create one component prop for the ~SayNow~ component:
~dateTime~. It gets passed from the ~App~ component. The ~SayNow~
component prints out the ~DateTime~ passed in to it. You might notice
@@ -787,17 +785,17 @@ setInterval(() =>
1000);
#+END_SRC
If you run the code above you will see the DateTime display being
updated every second. And if you watch in your dev tools or if you
profile the run you will see that the only part of the DOM that gets
If you run the code above you’ll see the DateTime display being
updated every second. And if you watch in your dev tools, or if you
profile the run, you’ll see that the only part of the DOM that gets
updated or replaced is the part that changes (aside from the DOM
props). We now have a working version of our own React.
#+begin_note
This implementation is designed for teaching purposes and has some
known issues and bugs, like always updating the DOM props, along with
other things. Fundamentally, it functions the same as React but if you
wanted to use it in a more production setting it would take a lot more
known bugs, like always updating the DOM props, along with
other issues. Fundamentally, it functions the same as React, but if you
want to use it in a more production-like setting, it would take a lot more
development.
#+end_note
@@ -808,7 +806,7 @@ development.
Of course our version of React elides over many details that React
must contend with, like starting a re-render from where state changes
and event handlers. For understanding how to build high-performance
and event handlers. To build high-performance
React applications, however, the most important piece to understand is
how and when React renders components, which is what we have learned
in creating our own mini version of React.
@@ -820,11 +818,11 @@ components, and how React chooses when to replace a node or re-use
one. If your React application is performing poorly you can think
about which part of the algorithm or heuristics might be the issue.
Now, there is a lot more to explore. Like how do you track down the
cause of a performance bottleneck? Or how do you use the React APIs in
Now, there is a lot more to explore. Like, how do you track down the
cause of a performance bottleneck? Or, how do you use the React APIs in
a performant way? These types of questions should be easier to track
down and understand with the foundations covered and I hope this is
only the start of your High-Performance React journey.
down and understand with the foundations we covered. So I hope this is
just the start of your high-performance React journey.
* Image Test :noexport:
:PROPERTIES:
:EXPORT_FILE_NAME: manuscript/image-test.markua