Checkout my Getting Started with React video course on Skillshare. It is 100% free.

Tools of the trade: the CSS grid generator and the CSS selector explainer

Today I want to share with you guys two sites I've have found recently. Both of them quite useful for our CSS endeavors.

The first one is the CSS grid generator made by Sarah Drasner. Define a grid, select the areas where you want the content to be, how big it should be, the spacing and the generator will give you the code to make it happen. Good to use when you want to learn or make some fast sketches using CSS grid.

And the second is the Selectors Explained tool. It's super cool. You give it a selector and it will show a nice "plain English explanation" for what that selector means alongside its CSS specificity score.

For example, if you give it:

#main-from > input[type=text] 

It will give back: "An input element with an attribute type whose value is text … directly within the element with id main-from". And with a specificity score of 1.1.1.

Pretty neat, no !? Btw, here you can find also 2 games for learning CSS grid and Felxbox.

Video – Using XHR breakpoints to intercept HTTP calls in Chrome Devtools

Last week I've found myself in a tricky caching situation where I could not say exactly was happening with an Ajax call.

Mike Sherov was kind enough to show me how we can use the Google Chrome Devtools to pause any Javascript execution when an HTTP call is made and point to where that call was made from.

I made a short video about it. Hope you like it.

By the way, check Mike's courses on egghead about Web Security Essentials and JavaScript ES2019 in Practice. They are super good!

How to better market yourself as a React developer

Usually, I stay away from topics like "personal branding". I can see the value of this concept, but a lot of the talks surrounding it are full of bla bla.

However, I've recently discovered this recording on youtube by Shawn Wang.

What I like about this talk is that you have a lot of high applicable, practical information that you may get from something a programming screencast. Especially in the first half.

I also liked that it uses a lot of examples from the React community. How guys like Wes Bos or Kent C. Dodds build their brand. Also, it gives some great tips on where to find React and Javascript side project ideas to add to your CV.

So, go ahead, give it a try:

Selecting the full text with just one click in CSS

In CSS we can use the user-select property to decide how the user can select the text.

By default, a user has to drag and hold the cursor to select the wateded text. But thanks to the user-select prop we can select a full text with just one click:

.select-all-text {
    user-select: all;
    -moz-user-select: all;
    -webkit-user-select: all;

And you can apply the .select-all-text class the whatever element is needed. A paragrpah, a div and so on.

But you can also have a no-select option if you don't want to allow any selection, or copy paste at all.

.no-select-allowed {
    user-select: none;
    -moz-user-select: none;
    -webkit-user-select: none;

Below is a full Codepen example with these options in action.

See the Pen
CSS User Select
by JS Craft (@js-craft)
on CodePen.

PS: if you want to reved to the default way of selecting the text you can say:

.default-select {
    user-select: auto;
    -moz-user-select: auto;
    -webkit-user-select: auto;

When to use CSS grid and when to use flexbox

There are cases when it's a bit confusing to decide if one should use flexbox or the CSS grid for the layouts. Till a point, both of them are interchangeable.

Maybe the best, and the shortest definition of the difference between Flexbox and CSS grid : Flexbox is for one-dimensional layout. A row OR a column. Grid is for two-dimensional layout. Rows AND columns.

It's from a tweet of Rachel Andrew (read her blog; it's fantastic).

So if we have a case like this, with just one dimension flexbox is a good fit.

Meanwhile, a case like this is more suited for a CSS grid.

However, keep in mind that a flexbox layout can "flow" on multiple rows if it does not have enough space for its elements. But it's still unidimensional.

But if we look at a design like this, the blue rectangle is set on two dimensions so CSS grid is the way to go.

Also, in this video, Jen Simmons explains how they’re different, and when you should choose one over the other.


Beyond console.log() – 3 Console methods you can use for better Javascript debugging

We can enhance our Javascript debugging experience using a set of less known features of the Console utility.

1. Using CSS with console.log

You can style your console log messages. You need to add the %c flag alongside a second parameter containing the actual CSS styles. For example:

console.log("%cA green message", "background-color: green; padding: 5px; color: white");

will output the following:

2. Using console.table() and console.dir() to print objects.

The plain console.log() is meant to print single lines. However, if you want to print objects console.table() and console.dir() are a better fit.

For example, if we have the following objects:

const firstChar = {name: "Han Solo", age: 35};
const secondChar = {name: "Chewbacca", age: 190};

The console.table(firstChar) will give the following nice formatted output:

And we can use table also with an array of objects.

console.table([firstChar, secondChar]);

Will output:

3. Adding new flavors: console.warn() and console.error()

And maybe the easiest commands to add to your toolbelt are the different levels of errors in showing up a message:

console.log("a simple log"); // no alter
console.warn("pay attention!"); // yellow alert 
console.error("a serious error !!!"); // red alert

This will output:

Disclaimer: when it comes to finding what is wrong with your Javascript code, please keep in mind that in the vast majority of cases it's faster to use tools like the javascript debugger from Google Chrome DevTools or Firefox instead of the plain old console.log.

Why use the :root pseudo selector to define CSS variables

o my shame, I have found about the CSS :root selector only a few weeks ago when I was changing some styling in the WordPress theme of this blog.

I've seen a piece of code similar to the one below:

:root {
    --color__success: #1fc281;
    --color__info: #00b9f2;
    --color__warning: #f4cc31;
    --color__danger: #e83337;

I've recognized the declarations of the CSS variables but what was that :root thing doing there !?

And started to read more about it.

Long story short. The :root is referring to the highest-level parent of a given specification. In the HTML specification, the :root is essentially the same as the html selector.

But, CSS is also designed for SVG. So, we can use :root to select the highest-level parent of a given specification even if is HTML, CSS or XML.

This means that if we want to define global properties, like CSS color variables, we will use :root and those variables will be available both in HTML and SVG.

:root { 
    margin: 0; 
    padding: 0; 
    --main-color: #ff1100; 

html {
    color: var(--main-color);

svg {
    fill: var(--main-color);

And also keep in mind that root is a pseudo selector. This means it will have a higher specificity that the html element selector.

:root { 
    background-color: red; 
    color: white; 
html {
    background-color: red; 
    color: white;

How CSS resolves conflicts: the specificity rule

There are two main ways of how CSS deals with conflicting rules: specificity and cascading. In this article, we will focus on specificity.

Take the following example:

div p { color: green;}
p { color: red;}     

Applied to this HTML:

<body id="home-page" class="blog">
    <div class="intro">
        <p> some content</p>

The cascading rule in CSS will indicate that the paragraph should be reb, given the last rule. However, we will see that the paragraph is green. And that is because of the first rule is more specific than the last rule.

ok, but what happens if we have a CSS like this one: { color: green;}
.intro .blog p { color: blue; }
#home-page { color: orange;}
body div p { color: red;}      

With the HTML being the same, what color will the paragraph be in this case?

How CSS specificity is calculated?

The CSS power can be determined by calculating the sum of all the selectors that are used in that statement. For this we can use the following table:

The most powerful selectors are the ID's (100 specificity points) , followed by classes (10 specificity points), and finally the elements selectors (just 1 specificity points each).

The pseudo-class selectors (for example :hover, :before or :after) and the attributes selectors have the same power as a class selector (10 points).

So, with this knowledge, let's calculate the specificity levels in our example: { color: green;}
// one ID and one CLASS
// #home-page(100) + .blog(10)  = 110

.intro .blog p { color: blue; }
// two CLASS and one ELEMENT
// .intro(10) + .blog(10) + p(1) = 21

#home-page { color: orange;}
// one ID 
// #home-page (100) = 100

body div p { color: red;}       
// three elements  
// body(1)  + div(1) + p(1) = 3    

So the first rule gets the most specificity power, with 110 points making the text green colored.

Also, keep in mind that specificity is more powerful than cascading. However, if we have conflicting rules, with the same specificity then the result will be determined based on the cascading / order.


div p { color: green;}
// div (1) + p (1)  = 2

body p { color: blue; }
// body(1) + p (1)  = 2

// same specifity; the last rule wins
// paragraph is blue

What about the specificity of !important and inline styles

In normal circumstances, we should avoid as much as possible to use both !important and inline styles. But if we have to, keep in mind that inline styles count as 1000 points, and !important is even more powerful with 10.000 points.

So the full table of specificity points looks like this:

Alright friends, that's all for now! Have a fantastic day 🙂

Defining names for lines in CSS grid

The CSS Grid uses lines to position the elements. By default, we can use line numbers to place the elements.

But if you find notations like .header { grid-column: 1 / 3; } confusing then we can define name for these lines.

The name defining is done in the grid-template-columns (and, if needed, in the grid-template-rows):

.container {
    display: grid;
    grid-template-columns: [article-start] 2fr [picture-start] 1fr [nav-start] 80px [nav-end];

So now we can say:

.header {
    grid-column: article-start / nav-start;
.article {
    grid-column: article-start/picture-start;
.picture {
    grid-column: picture-start / nav-start;
.navigation {
    grid-column: nav-start / nav-end;

Check out below the full working example.

See the Pen
Using names for CSS grid lines
by JS Craft (@js-craft)
on CodePen.

Defining multiple names for the same lines

But wait, there is more! We can define more that one name for a line.

It would be cool to define our article with something like article-start to article-end.

However, the article-end will be the starting point for the picture section. This means that we will then have to write for the picture: grid-row: article-end / nav-start; instead of an ideal grid-row: picture-start / picture-end;

In most cases, the ending point for something is the starting point for something else. So, therefore, the need to have multiple names for the same line.

We can implement this by just adding an extra name in the square brackets.

.container {
      [article-end picture-start] 
      [picture-end nav-start] 

So that we can now say:

.picture {
    grid-row: picture-start / picture-end;

Check out here the codepen with multiple names for the same lines. Cheers!

How and why to use the repeat function in CSS Grid

Let's say we have a layout made of 10 equal-width columns. Then the container element will look like this:

.container {
    grid-template-columns: 1fr 1fr 1fr 1fr 1fr 1fr 1fr 1fr 1fr 1fr;

It's a bit troublesome to write a line where you paste ten times the same 1fr. Imagine how fun it's to read this line. Luckily we have the repeat function for situations like this one.

.container {
    grid-template-columns: repeat(10, 1fr);

A big readability improvement. You tell the function how many times to repeat, and what to repeat.

If works for both the grid-template-columns and grid-template-rows.

We can give it also a pattern to repeat:

.container {
    grid-template-columns: repeat(3, 1fr 50px);
    // it will create 6 columns
    // 1fr 50px 1fr 50px 1fr 50px 

Using the CSS grid repeat function with named lines

And we can even use it with named lines.

.container {
    grid-template-columns: repeat(3, [col-start ] 1fr [col-end] );
    // it will create 3 columns
    // [cstart ] 1fr  [cend] [cstart ] 1fr  [cend]  [cstart ] 1fr  [cend] 

Given the fact that we will have the same name for the columns, we will need to a second parameter in the grid-column to indicate instance number of the name we want to place an element:

.my-element {
    grid-column: cstart 2 / cend 2;

Using the repeat function with auto-fill

But what if we want to have a layout where we want to have as many columns of 200px as they fit in the width of the container? Well, for this we can use the auto-fill:

.container {
    grid-template-columns: repeat( auto-fill , 200px );
    // it will  make as many 200px columns as possible 
    // eq: your screen is 1500px , it will make 7 columns

And that's all for now, folks! Have a fantastic day!