How to create a Timeline Component with React

#react #javascript #programming

These days I've been working on a new page for my website. I wanted to have a Timeline to showcase some of my professional accomplishments over the years.

I did it for a couple of reasons:

My future self will look back one day and say: "Wow... I remember the day when I did that! How happy I was to achieve that goal!". Our success is a journey, not a destination and I want to write down every goal that I achieve along the way
It might attract more clients (we'll see how this goes 😄)
In my opinion it is a different kind of portfolio. A unique portfolio, maybe? 😜

Nevertheless... Let's build something now!

In the picture above you can see what we're going to build today using React! Before we start let's break down the steps we need to take:

Create the data that we'll need
Create the TimelineItem component - each individual timeline entry
Create a Timeline container - it will take the data and pass it down to the TimelineItems
Style everything

Create the data

Before we move to actually create the React components we need to know exactly how the data is going to look so we can plan out the DOM structure.

For this Timeline app we're going to need an array of objects. We will call this array: timelineData.

Let's see how it might look:

[
    {
        text: 'Wrote my first blog post ever on Medium',
        date: 'March 03 2017',
        category: {
            tag: 'medium',
            color: '#018f69'
        },
        link: {
            url:
                'https://medium.com/@popflorin1705/javascript-coding-challenge-1-6d9c712963d2',
            text: 'Read more'
        }
    },
    {
        // Another object with data
    }
];

The properties are pretty straightforward, right? I used similar data to what I have on my timeline page, so we can say that this is production ready! 😆

Next, we'll build the TimelineItem component. This will use the data from the object above:

The TimelineItem component

const TimelineItem = ({ data }) => (
    <div className="timeline-item">
        <div className="timeline-item-content">
            <span className="tag" style={{ background: data.category.color }}>
                {data.category.tag}
            </span>
            <time>{data.date}</time>
            <p>{data.text}</p>
            {data.link && (
                <a
                    href={data.link.url}
                    target="_blank"
                    rel="noopener noreferrer"
                >
                    {data.link.text}
                </a>
            )}
            <span className="circle" />
        </div>
    </div>
);

We have the following tags:

.timeline-item div - used as a wrapper. This div will have half the width of it's parent's width (50%) and every other .timeline-item div will be placed to the right side using the :nth-child(odd) selector
.timeline-item-content div - another wrapper (more on why we need this in the styling section)
.tag span - this tag will have a custom background color depending on the category
the time/date and the text
link - we will need to check this to see if a link is provided because we might not always want to have one
.circle span - this tag will be used to place a circle on the middle line/bar

Note: Everything will make much more sense when we get to the CSS/styling part, but before that let's create the Timeline component:

The Timeline container

This component will basically map over the array and for each object it will create a TimelineItem component. We also add a small check to make sure that there is at least one element in the array:

import timelineData from '_path_to_file_';

const Timeline = () =>
    timelineData.length > 0 && (
        <div className="timeline-container">
            {timelineData.map((data, idx) => (
                <TimelineItem data={data} key={idx} />
            ))}
        </div>
    );

As mentioned above, the timelineData is the array of objects containing all the required information. In my case I stored this array in a file and I imported it here, but you can take this from your own database or from an API endpoint, it's up to you.

The CSS

Note that most of the wrappers will be flexbox containers because we can play around easier with their positioning. Let's start with the .timeline-container CSS:

.timeline-container {
    display: flex;
    flex-direction: column;
    position: relative;
    margin: 40px 0;
}

.timeline-container::after {
    background-color: #e17b77;
    content: '';
    position: absolute;
    left: calc(50% - 2px);
    width: 4px;
    height: 100%;
}

We're using the ::after selector to create that red line/bar in the middle of the .timeline-container. Using the calc() function we can position the line exactly in the middle by subtracting half of it's size (2px) from 50%. We need to do this because by default the left property positions it according to the left edge of an element and not the middle.

Now, let's move to the .timeline-item wrapper.

Below you can see an example of how these are positioned within their parent (the .timeline-container). For demonstration purposes I added a border to highlight these wrappers:

As you can see, every other wrapper goes to the right, and the inner wrapper (the .timeline-item-content) is taking less space - space given by the p tag which is inside it (mostly). Let's see the CSS for this:

.timeline-item {
    display: flex;
    justify-content: flex-end;
    padding-right: 30px;
    position: relative;
    margin: 10px 0;
    width: 50%;
}

.timeline-item:nth-child(odd) {
    align-self: flex-end;
    justify-content: flex-start;
    padding-left: 30px;
    padding-right: 0;
}

The key to this is that we use the :nth-child(odd) selector and we set the align-self property to flex-end which means: "Go to the right as much as you can"!

Because these wrappers are 50% in width, you can see that two of them take up the whole width. From now on, every time we want to style differently something in the right side, we'll have to use this approach.

Next, the .timeline-item-content wrapper:

.timeline-item-content {
    box-shadow: 0 0 5px rgba(0, 0, 0, 0.3);
    border-radius: 5px;
    background-color: #fff;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    padding: 15px;
    position: relative;
    width: 400px;
    max-width: 70%;
    text-align: right;
}

.timeline-item-content::after {
    content: ' ';
    background-color: #fff;
    box-shadow: 1px -1px 1px rgba(0, 0, 0, 0.2);
    position: absolute;
    right: -7.5px;
    top: calc(50% - 7.5px);
    transform: rotate(45deg);
    width: 15px;
    height: 15px;
}

.timeline-item:nth-child(odd) .timeline-item-content {
    text-align: left;
    align-items: flex-start;
}

.timeline-item:nth-child(odd) .timeline-item-content::after {
    right: auto;
    left: -7.5px;
    box-shadow: -1px 1px 1px rgba(0, 0, 0, 0.2);
}

We have a few things going on:

This wrapper has a fixed width and also a max-width. This is because we want it to have some boundaries, meaning that if there are only a few words, we want the box to be at least 400px wide, but if there is a lot of text, it shouldn't take up the full space (the 50% from the .timeline-item wrapper) but the text should move on to the next line -> this is the reason we used this second wrapper: .timeline-item-content
The text-align and align-items properties are used to push the inner elements to the left or to the right, depending on the parent
The small arrow that points to the middle line is given by the styles applied on the ::after selector. Basically it is a box with a box-shadow applied on it that is rotated 45deg
As mentioned above, we style the right side by selecting the parent with the :nth-child(odd) selector

Next up, all the inner elements:

.timeline-item-content .tag {
    color: #fff;
    font-size: 12px;
    font-weight: bold;
    top: 5px;
    left: 5px;
    letter-spacing: 1px;
    padding: 5px;
    position: absolute;
    text-transform: uppercase;
}

.timeline-item:nth-child(odd) .timeline-item-content .tag {
    left: auto;
    right: 5px;
}

.timeline-item-content time {
    color: #777;
    font-size: 12px;
    font-weight: bold;
}

.timeline-item-content p {
    font-size: 16px;
    line-height: 24px;
    margin: 15px 0;
    max-width: 250px;
}

.timeline-item-content a {
    font-size: 14px;
    font-weight: bold;
}

.timeline-item-content a::after {
    content: ' ►';
    font-size: 12px;
}

.timeline-item-content .circle {
    background-color: #fff;
    border: 3px solid #e17b77;
    border-radius: 50%;
    position: absolute;
    top: calc(50% - 10px);
    right: -40px;
    width: 20px;
    height: 20px;
    z-index: 100;
}

.timeline-item:nth-child(odd) .timeline-item-content .circle {
    right: auto;
    left: -40px;
}

Few things to note here:

As you might have guessed, the .tag is positioned absolute because we want to keep it in the top left (or right) corner no matter what size is the box
We want to add a small caret after the a tag to highlight that it is a link
We create a .circle and position it on top of the middle line/bar directly in front of the arrow

We're almost done! 😄 The only thing that's left to do is to add the CSS to make everything responsive across all screen sizes:

@media only screen and (max-width: 1023px) {
    .timeline-item-content {
        max-width: 100%;
    }
}

@media only screen and (max-width: 767px) {
    .timeline-item-content,
    .timeline-item:nth-child(odd) .timeline-item-content {
        padding: 15px 10px;
        text-align: center;
        align-items: center;
    }

    .timeline-item-content .tag {
        width: calc(100% - 10px);
        text-align: center;
    }

    .timeline-item-content time {
        margin-top: 20px;
    }

    .timeline-item-content a {
        text-decoration: underline;
    }

    .timeline-item-content a::after {
        display: none;
    }
}

We have two media queries:

On small laptop screen sizes - max-width: 1023px - we want to allow the .timeline-item-content to go across the entire width of it's parent because the screen is smaller and otherwise it would look squeezed
On phones - max-width: 767px
- set the .tag to be full width (and for that we don't need to forget to subtract 10px from the total of 100% - this is because we have it positioned at left: 5px, so we remove double of this amount)
- center all the text and push it down from the top just a little bit
- remove the caret on the link and add an underline - looks better on mobile 😉