Iconify icon component is nothing like that. Component does not include any icon data, it is not tied to any specific icon set. Instead, all data is retrieved from public API on demand.
Component will automatically retrieve data for "mdi-light:home" from Iconify API and render it. There are over 200,000 icons available on Iconify API from various free and open source icon sets, including all the most popular icon sets.
If you are experiencing issues with SSR hydration, there is an alternative solution available: [Iconify Icon web component](https://iconify.design/docs/iconify-icon/).
Web component is preferred to this component if:
- Your page is performing slowly. Web component separates icon rendering in shadow DOM, improving performance.
Example above might currently fail with some use cases. Package `@iconify-icons/mdi-light` uses ES modules that some software might not support yet. But do not worry, there is a simple solution: switch to CommonJS icon packages.
To switch to CommonJS package, replace this line in example above:
```js
import home from '@iconify-icons/mdi-light/home';
```
with
```js
import home from '@iconify/icons-mdi-light/home';
```
All icons are available as ES modules for modern bundler and as CommonJS modules for outdated bundlers. ES modules use format `@iconify-icons/{prefix}`, CommonJS modules use `@iconify/icons-{prefix}`.
Icons have 2 modes: inline and block. Difference between modes is `vertical-align` that is added to inline icons.
Inline icons are aligned slightly below baseline, so they look centred compared to text, like glyph fonts.
Block icons do not have alignment, like images, which aligns them to baseline by default.
Alignment option was added to make icons look like continuation of text, behaving like glyph fonts. This should make migration from glyph fonts easier.
To toggle between block and inline modes, you can either boolean `inline` property.
`icon` attribute is mandatory. It tells component what icon to render. If the attribute value is invalid, the component will render an empty icon. The value must be an object containing the icon data.
The icon component has the following optional attributes:
-`inline`. Changes icon behaviour to match icon fonts. See "Inline icon" section below.
-`width` and `height`. Icon dimensions. The default values are "1em" for both. See "Dimensions" section below.
-`color`. Icon colour. This is the same as setting colour in style. See "Icon colour" section below.
In addition to the attributes mentioned above, the icon component accepts any other attributes. All other attributes will be passed to generated `SVG` element, so you can do stuff like setting the inline style, add title and so on.
In Svelte it is not possible to pass events to child components, so Icon component does not handle any events. If you need to make icon clickable, wrap it in a button or link and assign an event to that button or link.
### Dimensions
By default, icon height is "1em". With is dynamic, calculated using the icon's width to height ratio.
There are several ways to change icon dimensions:
- Setting `font-size` in style.
- Setting `width` and/or `height` attribute.
Values for `width` and `height` can be numbers or strings.
If you set only one dimension, another dimension will be calculated using the icon's width to height ratio. For example, if the icon size is 16 x 24, you set the height to 48, the width will be set to 32. Calculations work not only with numbers, but also with string values.
Be careful when using `calc`, view port based units or percentages. In SVG element they might not behave the way you expect them to behave and when using such units, you should consider settings both width and height.
#### Dimensions as 'auto'
Keyword "auto" sets dimensions to the icon's `viewBox` dimensions. For example, for 24 x 24 icon using `height="auto"` sets height to 24 pixels.
There are two types of icons: icons that do not have a palette and icons that do have a palette.
Icons that do have a palette, such as emojis, cannot be customised. Setting colour to such icons will not change anything.
Icons that do not have a palette can be customised. By default, colour is set to "currentColor", which means the icon's colour matches text colour. To change the colour you can:
- Set `color` style or use stylesheet to target icon. If you are using the stylesheet, target `svg` element. If you are using scoped style, use `:global(svg)` to target `svg` element.
This might seem redundant because icon can also be rotated and flipped using CSS transformations. So why do transformation attributes exist? Because it is a different type of transformation.
- CSS transformations transform the entire icon.
- Icon transformations transform the contents of the icon.
If you have a square icon, this makes no difference. However, if you have an icon that has different width and height values, it makes a huge difference.
Rotating 16x24 icon by 90 degrees results in:
- CSS transformation keeps 16x24 bounding box, which might cause the icon to overlap text around it.
- Icon transformation changes bounding box to 24x16, rotating content inside an icon.
What is the purpose of `onLoad`? To let you know when Icon component renders an icon and when it does not render anything. This allows you to do things like adding class name for parent element, such as "container--with-icon" that modify layout if icon is being displayed.
If you use the component as shown in examples above, SVG will be rendered on the server and sent to visitor as HTML code.
If you are rendering multiple identical icons, rendering them on server is not optimal. It is much better to render them once using JavaScript in browser. How to do that with this icon component? By loading both component and icon data asynchronously.
Example:
```jsx
<script>
// Dynamically load icon component, icon data and render it on client side
This example adds an icon stored in `postIcon` to every list item. If it was rendered on the server, HTML would send SVG element multiple times. But because it is rendered in the browser, icon data and component needs to be sent to the browser only once.
