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knobs

README.md

Storybook Addon Knobs

Storybook Addon Knobs allow you to edit props dynamically using the Storybook UI. You can also use Knobs as a dynamic variable inside stories in Storybook.

Framework Support

This is how Knobs look like:

Storybook Knobs Demo

Checkout the above Live Storybook or watch this video.

Getting Started

First of all, you need to install knobs into your project as a dev dependency.

yarn add @storybook/addon-knobs --dev

Then, configure it as an addon by adding it to your addons.js file (located in the Storybook config directory).

import '@storybook/addon-knobs/register';

Now, write your stories with knobs.

With React

import { storiesOf } from '@storybook/react';
import { withKnobs, text, boolean, number } from '@storybook/addon-knobs';

const stories = storiesOf('Storybook Knobs', module);

// Add the `withKnobs` decorator to add knobs support to your stories.
// You can also configure `withKnobs` as a global decorator.
stories.addDecorator(withKnobs);

// Knobs for React props
stories.add('with a button', () => (
  <button disabled={boolean('Disabled', false)} >
    {text('Label', 'Hello Storybook')}
  </button>
));

// Knobs as dynamic variables.
stories.add('as dynamic variables', () => {
  const name = text('Name', 'Arunoda Susiripala');
  const age = number('Age', 89);

  const content = `I am ${name} and I'm ${age} years old.`;
  return (<div>{content}</div>);
});

With Vue.js

MyButton.story.js:

import { storiesOf } from '@storybook/vue';
import { withKnobs, text, boolean } from '@storybook/addon-knobs';

import MyButton from './MyButton.vue';

const stories = storiesOf('Storybook Knobs', module);

// Add the `withKnobs` decorator to add knobs support to your stories.
// You can also configure `withKnobs` as a global decorator.
stories.addDecorator(withKnobs);

// Assign `props` to the story's component, calling
// knob methods within the `default` property of each prop,
// then pass the story's prop data to the component’s prop in
// the template with `v-bind:` or by placing the prop within
// the component’s slot.
stories.add('with a button', () => ({
  components: { MyButton },
  props: {
    isDisabled: {
      default: boolean('Disabled', false)
    },
    text: {
      default: text('Text', 'Hello Storybook')
    }
  },
  template: `<MyButton :isDisabled="isDisabled">{{ text }}</MyButton>`
}));

MyButton.vue:

<template>
  <button :disabled="isDisabled">
    <slot></slot>
  </button>
</template>

<script>
export default {
  props: {
    isDisabled: {
      type: Boolean,
      default: false
    }
  }
}
</script>

With Angular

import { storiesOf } from '@storybook/angular';
import { boolean, number, text, withKnobs } from '@storybook/addon-knobs';

import { Button } from '@storybook/angular/demo';

const stories = storiesOf('Storybook Knobs', module);

// "withKnobs" decorator should be applied before the stories using knobs
stories.addDecorator(withKnobs);

// Knobs for Angular props
stories.add('with a button', () => ({
  component: Button,
  props: {
   text: text('text', 'Hello Storybook'), // The first param of the knob function has to be exactly the same as the component input.
  },
}));

Categorize your knobs by assigning them a groupId. When a groupId exists, tabs will appear in the knobs storybook panel to filter between the groups. Knobs without a groupId are automatically categorized into the ALL group.

// Knob assigned a groupId.
stories.add('as dynamic variables', () => {
  const groupId = 'GROUP-ID1'
  const name = text('Name', 'Arunoda Susiripala', groupId);

  const content = `My name is ${name}.`;
  return (<div>{content}</div>);
});

You can see your Knobs in a Storybook panel as shown below.

Available Knobs

These are the knobs available for you to use. You can import these Knobs from the @storybook/addon-knobs module. Here's how to import the text Knob.

import { text } from '@storybook/addon-knobs';

Just like that, you can import any other following Knobs:

text

Allows you to get some text from the user.

import { text } from '@storybook/addon-knobs';

const label = 'Your Name';
const defaultValue = 'Arunoda Susiripala';
const groupId = 'GROUP-ID1';

const value = text(label, defaultValue, groupId);

boolean

Allows you to get a boolean value from the user.

import { boolean } from '@storybook/addon-knobs';

const label = 'Agree?';
const defaultValue = false;
const groupId = 'GROUP-ID1';

const value = boolean(label, defaultValue, groupId);

number

Allows you to get a number from the user.

import { number } from '@storybook/addon-knobs';

const label = 'Age';
const defaultValue = 78;
const groupId = 'GROUP-ID1';

const value = number(label, defaultValue);

For use with groupId, pass the default options as the third argument

const value = number(label, defaultValue, {}, groupId);

number bound by range

Allows you to get a number from the user using a range slider.

import { number } from '@storybook/addon-knobs';

const label = 'Temperature';
const defaultValue = 73;
const options = {
   range: true,
   min: 60,
   max: 90,
   step: 1,
};
const groupId = 'GROUP-ID1';

const value = number(label, defaultValue, options, groupId);

color

Allows you to get a colour from the user.

import { color } from '@storybook/addon-knobs';

const label = 'Color';
const defaultValue = '#ff00ff';
const groupId = 'GROUP-ID1';

const value = color(label, defaultValue, groupId);

object

Allows you to get a JSON object or array from the user.

import { object } from '@storybook/addon-knobs';

const label = 'Styles';
const defaultValue = {
  backgroundColor: 'red'
};
const groupId = 'GROUP-ID1';

const value = object(label, defaultValue, groupId);

Make sure to enter valid JSON syntax while editing values inside the knob.

array

Allows you to get an array of strings from the user.

import { array } from '@storybook/addon-knobs';

const label = 'Styles';
const defaultValue = ['Red'];
const groupId = 'GROUP-ID1';

const value = array(label, defaultValue);

While editing values inside the knob, you will need to use a separator. By default it's a comma, but this can be override by passing a separator variable.

import { array } from '@storybook/addon-knobs';

const label = 'Styles';
const defaultValue = ['Red'];
const separator = ':';
const value = array(label, defaultValue, separator);

For use with groupId, pass the default separator as the third argument

const value = array(label, defaultValue, ',', groupId);

select

Allows you to get a value from a select box from the user.

import { select } from '@storybook/addon-knobs';

const label = 'Colors';
const options = {
  Red: 'red',
  Blue: 'blue',
  Yellow: 'yellow',
  Rainbow: ['red', 'orange', 'etc'],
  None: null,
};
const defaultValue = 'red';
const groupId = 'GROUP-ID1';

const value = select(label, options, defaultValue, groupId);

You can also provide options as an array like this: ['red', 'blue', 'yellow']

radio buttons

Allows you to get a value from a list of radio buttons from the user.

import { radios } from '@storybook/addon-knobs';

const label = 'Fruits';
const options = {
      Kiwi: 'kiwi',
      Guava: 'guava',
      Watermelon: 'watermelon',
};
const defaultValue = 'kiwi';
const groupId = 'GROUP-ID1';

const value = radios(label, options, defaultValue, groupId);

options

Configurable UI for selecting a value from a set of options.

import { optionsKnob as options } from '@storybook/addon-knobs';

const label = 'Fruits';
const valuesObj = {
  Kiwi: 'kiwi',
  Guava: 'guava',
  Watermelon: 'watermelon',
};
const defaultValue = 'kiwi';
const optionsObj = {
  display: 'inline-radio'
};
const groupId = 'GROUP-ID1';

const value = options(label, valuesObj, defaultValue, optionsObj, groupId);

The display property for optionsObj accepts:

  • radio
  • inline-radio
  • check
  • inline-check
  • select
  • multi-select

files

Allows you to get a value from a file input from the user.

import { files } from '@storybook/addon-knobs';

const label = 'Images';
const accept = '.xlsx, .pdf';
const defaultValue = [];
const groupId = 'GROUP-ID1';

const value = files(label, accept, defaultValue, groupId);

You can optionally specify a list of file types which the file input should accept. Multiple files can be selected, and will be returned as an array of Data URLs.

date

Allow you to get date (and time) from the user.

import { date } from '@storybook/addon-knobs';

const label = 'Event Date';
const defaultValue = new Date('Jan 20 2017');
const groupId = 'GROUP-ID1';

const value = date(label, defaultValue, groupId);

Note: the default value must not change - e.g., do not do date('Label', new Date()) or date('Label')

The date knob returns the selected date as stringified Unix timestamp (e.g. "1510913096516"). If your component needs the date in a different form you can wrap the date function:

function myDateKnob(name, defaultValue) {
  const stringTimestamp = date(name, defaultValue)
  return new Date(stringTimestamp)
}

button

Allows you to include a button and associated handler.

import { button } from '@storybook/addon-knobs';

const label = 'Do Something';
const handler = () => doSomething('foobar');
const groupId = 'GROUP-ID1';

button(label, handler, groupId);

Button knobs cause the story to re-render after the handler fires, you can prevent this by having the handler return false.

withKnobs options

withKnobs also accepts two optional options as story parameters. Usage:

import { storiesOf } from '@storybook/react';
import { withKnobs } from '@storybook/addon-knobs';

const stories = storiesOf('Storybook Knobs', module);

stories.addDecorator(withKnobs)
stories.add('story name', () => ..., {
  knobs: {
    timestamps: true, // Doesn't emit events while user is typing.
    escapeHTML: true // Escapes strings to be safe for inserting as innerHTML. This option is true by default. It's safe to set it to `false` with frameworks like React which do escaping on their side.
                     // You can still set it to false, but it's strongly unrecommendend in cases when you host your storybook on some route of your main site or web app.
  }
});

Typescript

If you are using typescript, make sure you have the type definitions installed for the following libs:

  • node
  • react

You can install them using: assuming you are using Typescript >2.0.

yarn add @types/node @types/react --dev