---
title: "Shortcodes"
date: 2020-08-11
draft: false
description: "All the shortcodes available in Congo."
slug: "shortcodes"
tags: ["shortcodes", "mermaid", "icon", "lead", "docs"]
---

In addition to all the [default Hugo shortcodes](https://gohugo.io/content-management/shortcodes/), Congo adds a few extras for additional functionality.

## Alert

`alert` outputs its contents as a stylised message box within your article. It's useful for drawing attention to important information that you don't want the reader to miss.

The input is written in Markdown so you can format it however you please.

**Example:**

```md
{{</* alert */>}}
**Warning!** This action is destructive!
{{</* /alert */>}}
```

{{< alert >}}
**Warning!** This action is destructive!
{{< /alert >}}

## Badge

`badge` outputs a styled badge component which is useful for displaying metadata.

**Example:**

```md
{{</* badge */>}}
New article!
{{</* /badge */>}}
```

{{< badge >}}
New article!
{{< /badge >}}

## Button

`button` outputs a styled button component which can be used to highlight a primary action. It has two optional variables `href` and `target` which can be used to specify the URL and target of the link.

**Example:**

```md
{{</* button href="#button" target="_self" */>}}
Call to action
{{</* /button */>}}
```

{{< button href="#button" target="_self" >}}
Call to action
{{< /button >}}

## Chart

`chart` uses the Chart.js library to embed charts into articles using simple structured data. It supports a number of [different chart styles](https://www.chartjs.org/docs/latest/samples/) and everything can be configured from within the shortcode. Simply provide the chart parameters between the shortcode tags and Chart.js will do the rest.

Refer to the [official Chart.js docs](https://www.chartjs.org/docs/latest/general/) for details on syntax and supported chart types.

**Example:**

```js
{{</* chart */>}}
type: 'bar',
data: {
  labels: ['Tomato', 'Blueberry', 'Banana', 'Lime', 'Orange'],
  datasets: [{
    label: '# of votes',
    data: [12, 19, 3, 5, 2, 3],
  }]
}
{{</* /chart */>}}
```

<!-- prettier-ignore-start -->
{{< chart >}}
type: 'bar',
data: {
  labels: ['Tomato', 'Blueberry', 'Banana', 'Lime', 'Orange'],
  datasets: [{
    label: '# of votes',
    data: [12, 19, 3, 5, 3],
  }]
}
{{< /chart >}}
<!-- prettier-ignore-end -->

You can see some additional Chart.js examples on the [charts samples]({{< ref "charts" >}}) page.

## Icon

`icon` outputs an SVG icon and takes the icon name as its only parameter. The icon is scaled to match the current text size.

**Example:**

```md
{{</* icon "github" */>}}
```

**Output:** {{< icon "github" >}}

Icons are populated using Hugo pipelines which makes them very flexible. Congo ships with a default set of icons for social, email, and generic links. If you want to add your own icons, you can simply place them in `/assets/icons/` and reference them using the `icon` shortcode passing in the icon's filename (without the `.svg.` extension).

Icons can also be used in partials by calling the [icon partial]({{< ref "partials#icon" >}}).

## Katex

The `katex` shortcode can be used to add mathematical expressions to article content using the KaTeX package. Refer to the online reference of [supported TeX functions](https://katex.org/docs/supported.html) for the available syntax.

To include mathematical expressions in an article, simply place the shortcode anywhere with the content. It only needs to be included once per article and KaTeX will automatically render any markup on that page. Both inline and block notation are supported.

Inline notation can be generated by wrapping the expression in `\\(` and `\\)` delimiters. Alternatively, block notation can be generated using `$$` delimiters.

**Example:**

```md
{{</* katex */>}}
\\(f(a,b,c) = (a^2+b^2+c^2)^3\\)
```

{{< katex >}}
\\(f(a,b,c) = (a^2+b^2+c^2)^3\\)

Check out the [mathematical notation samples]({{< ref "mathematical-notation" >}}) page for more examples.

## Lead

`lead` is used to bring emphasis to the start of an article. It can be used to style an introduction, or to call out an important piece of information. Simply wrap any Markdown content in the `lead` shortcode.

**Example:**

```md
{{</* lead */>}}
When life gives you lemons, make lemonade.
{{</* /lead */>}}
```

{{< lead >}}
When life gives you lemons, make lemonade.
{{< /lead >}}

## Mermaid

`mermaid` allows you to draw detailed diagrams and visualisations using text. It uses Mermaid under the hood and supports a wide variety of diagrams, charts and other output formats.

Simply write your Mermaid syntax within the `mermaid` shortcode and let the plugin do the rest.

Refer to the [official Mermaid docs](https://mermaid-js.github.io/) for details on syntax and supported diagram types.

**Example:**

```md
{{</* mermaid */>}}
graph LR;
A[Lemons]-->B[Lemonade];
B-->C[Profit]
{{</* /mermaid */>}}
```

{{< mermaid >}}
graph LR;
A[Lemons]-->B[Lemonade];
B-->C[Profit]
{{< /mermaid >}}

You can see some additional Mermaid examples on the [diagrams and flowcharts samples]({{< ref "diagrams-flowcharts" >}}) page.
