@untemps/svelte-readotron
v2.0.0
Published
Svelte component to display an estimated reading time
Downloads
14
Maintainers
Readme
Demo
Installation
yarn add @untemps/svelte-readotron
Usage
Basic usage
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" />
<section class="text">...</section>
</main>
selector
prop is mandatory as it points to which element contains the text content to parse.
You can utilize any selector supported by the Web API querySelector function.
If several elements match the selector, it only parses the text of the first element in the array.
The component will wait for the element to be present in the DOM before parsing its content. If the element is not found after 1000ms, an error is raised and displayed.
This is achieved with the @untemps/dom-observer package.
Lang
'lang' is an optional prop that designates the language of the text to parse. The component implements the @untemps/read-per-minute underhand package which returns an estimation based on the lang (language).
Reading rates by lang come from "How many words do we read per minute? A review and meta-analysis of reading rate" by Marc Brysbaert - Department of Experimental Psychology Ghent University
| Lang | Rate | | ------- | ---- | | default | 200 | | ar | 181 | | zh | 260 | | nl | 228 | | en | 236 | | fi | 195 | | fr | 214 | | de | 260 | | he | 224 | | it | 285 | | ko | 226 | | es | 278 | | sv | 218 |
If a lang is not defined or the provided lang is not listed, the default value (200) will be applied.
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" lang="en" />
<section class="text">...</section>
</main>
Template
You can customize the Readotron display by using the template
prop.
- A template can be a string with one or more tokens delimited with
%
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" template="Reading Time: %time% minutes (%words% words)" />
<section class="text">...</section>
</main>
- A template can be a function with
time
andwords
as arguments.
The function should return a template literal with the markup to display using optionally arguments as placeholders. But it may return any displayable type as well.
:warning: The string will be parsed with the
{@html}
expression: Be very careful with the content you pass or allow to pass in to this prop!
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" template={(time, words) => `<Icon name='clock'> <strong>Reading Time: ${time} minutes</strong> (${words} words)`}/>
<section class="text">
...
</section>
</main>
Avalaible tokens/arguments
| Token | Description |
| ------- | ----------------------------------- |
| time
| Estimated reading time (in minutes) |
| words
| Number of words |
Scroll Support
You are able to track and update component values by opting in the withScroll
flag.
This will change the time
(remaining time to read) and words
(number of remaining words) as the user scroll the document.
Note: There is no support for
element
scrolling so far,document
only.
The component uses the scrollProgress underhand package to track document scrolling.
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" withScroll />
<section class="text">...</section>
</main>
Change Event
If you need to be notified whenever values change, you may attach a listener to the change
event emitted by the component.
Note: The change event will be dispatched only if the withScroll
prop is set to true
since this is the only use case that triggers the change event so far
The handler will be triggered for the first time during the mounting phase with the initial values.
Handler Signature
Here are the properties available inside the event.detail
sent with the event:
| Props | Type | Description |
| ---------- | ------ | --------------------------------------------- |
| time
| number | Estimated remaining reading time (in minutes) |
| words
| number | Number of remaining words |
| progress
| number | Ratio of progression (between 0 and 1) |
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" withScroll on:change={(event) => {
const {detail: {time, words, progress}} = event
console.log('Time:', time + ' minutes')
console.log('Words:', words + ' remaining words')
console.log('Progress:', progress * 100 + '%')
}}/>
<section class="text">
...
</section>
</main>
Recipe
The event dispatching allows to animate a progress bar in sync with the reading status:
<script>
import Readotron from '@untemps/svelte-readotron'
let readingProgress = 0
</script>
<main>
<Readotron selector=".text" withScroll on:change={(event) => {
readingProgress = event.detail.progress
}}/>
<section class="text">
...
</section>
<div class="progress-bar" style="width: {readingProgress * 100}%"></div>
</main>
<style>
.progress-bar {
background-color: #0075ff;
height: 20px;
position: fixed;
left: 0;
bottom: 0;
}
</style>
Slot
Another way to customize the display is to use the <slot>
element.
If a <slot>
is passed in as Readotron child and correctly set (see Constraints below), it will be rendered instead of the default layout. This has precedence over the template
prop.
This allows to set a specific tag as parent if needed.
Constraints:
The <slot>
element has to be set with the prop slot="content"
Avalaible tokens
Like template
, tokens are passed back to the component to display dynamic values (see Svelte API documentation):
| Token | Description |
| ------- | ----------------------------------- |
| time
| Estimated reading time (in minutes) |
| words
| Number of words |
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text">
<span slot="content" let:time let:words>{time} min ({words} words)</span>
</Readotron>
<section class="text">...</section>
</main>
Please see the Svelte API documentation to know more about the <slot>
element.
Styles
All HTML attributes are automatically passed to the parent element of the component (span
).
That means you can query the class
attribute to customize the style of the component.
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text" class="readotron" />
<section class="text">...</section>
</main>
<style>
.readotron {
color: #0075ff;
font-weight: 600;
}
</style>
If you use a <slot>
element, as it will replace the original layout, you have to switch the class name from the <Readotron>
element to the <slot>
element.
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text">
<span class="readotron" slot="content" let:time>{time} min</span>
</Readotron>
<section class="text">...</section>
</main>
Error
If an error occurs during the parsing phase, the component catches and exposes it through an error
variable which is displayed as is it by default. That means the error message uses the exact same styles as time value.
You may want to customize this error message, so the component provides a slot
, named error
, which replaces the default display if passed in.
Example
<script>
import Readotron from '@untemps/svelte-readotron'
</script>
<main>
<Readotron selector=".text">
<span class="readotron" slot="content" let:time>{time} min</span>
<span class="error" slot="error" let:error>Oops!</span>
</Readotron>
<section class="text">...</section>
</main>
<style>
.readotron {
color: #0075ff;
font-weight: 600;
}
.error {
color: #ff0000;
font-weight: 600;
}
</style>
Constraints:
The <slot>
element has to be set with the prop slot="error"
Avalaible tokens
Error message is passed back to the component for display purpose if needed (see Svelte API documentation):
| Token | Description |
| ------- | ---------------------- |
| error
| Original error message |
API
| Props | Type | Default | Description |
| ------------ | ------------------ | ----------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| selector
| string | (required) | Selector of the element which contains the content to parse. See document.querySelector |
| lang
| string | 'en' | Lang of the content [""ar', 'zh', 'nl', 'en', 'fi', 'fr', 'de', 'he', 'it', 'ko', 'es', 'sv'] |
| template
| string or function | '%time% min read' | Display template which contains dynamic tokens to be replaced by the parsed values. See Template |
| withScroll
| boolean | false | Enable updates on scroll. If true, time
and words
values will reflect the document scroll position |
Events
| Props | Arguments | Type | Description |
| -------- | ---------- | ------ | ------------------------------------------------------------------------------------------- |
| change
| | | Dispatches whenever time and words have changed |
| | time
| number | Estimated remaining reading time (in minutes) Estimated remaining reading time (in minutes) |
| | words
| number | Number of remaining words |
| | progress
| number | Ratio of progression (between 0 and 1) |
Development
The component can be served for development purpose on http://localhost:10001/
running:
yarn dev
Contributing
Contributions are warmly welcomed:
- Fork the repository
- Create a feature branch
- Develop the feature AND write the tests (or write the tests AND develop the feature)
- Commit your changes using Angular Git Commit Guidelines
- Submit a Pull Request