A custom element allowing a more declarative use of Redux.
MIT License
A custom element allowing a more declarative use of Redux.
This custom element offers the basic Redux API declaratively. Because this is a custom element based on the web components standards, it should be compatible with all major front-end JavaScript frameworks and libraries that interoperate with custom elements, including Polymer, SkateJS, Vue.js, Angular, vanilla JavaScript, etc. See here for more information on interoperability of other frameworks and libraries with custom elements.
Before we begin, I just want to highlight how easy it is to work with this element declaratively (using Polymer data binding syntax):
Hook up your root reducer (similar to Redux createStore
):
// HTML
<redux-store root-reducer="[[rootReducer]]"></redux-store>
// JS
import {RootReducer} from '../../redux/reducers';
...
connectedCallback() {
this.rootReducer = RootReducer;
}
Dispatch actions (similar to Redux dispatch
):
// HTML
<redux-store action="[[action]]"></redux-store>
// JS
fireAnAction() {
this.action = {
type: 'CHANGE_THE_STATE'
};
}
Listen for state changes (similar to Redux subscribe
):
// HTML
<redux-store on-statechange="stateChange"></redux-store>
[[valueToBind]]
// JS
stateChange(e) {
const state = e.detail.state;
this.valueToBind = state.valueToBind;
}
Explicitly grab the state (similar to Redux getState
):
// HTML
<redux-store id="redux-store-element"></redux-store>
// JS
getReduxState() {
const reduxStoreElement = this.querySelector('#redux-store-element');
const state = reduxStoreElement.getState();
}
Run the following:
npm install redux-store-element
Now import redux-store-element.js
:
// HTML
<script type="module" src="node_modules/redux-store-element/redux-store-element.js">
// JavaScript
import 'redux-store-element';
This custom element depends on the custom elements and HTML imports web component specifications, which are not supported by all browsers yet. Include the webcomponentjs polyfills to ensure support across all modern browsers:
// CONSOLE
npm install --save @webcomponents/webcomponentsjs
// HTML
<script src="node_modules/webcomponentsjs/webcomponents-lite.js"></script>
This custom element also depends on native ES Modules support and bare specifier support. Use a bundler like Rollup or Webpack if your environment doesn't support ES Modules. If your environment does support ES Modules and you do not wish to use a bundler, you will need to use a static file server that provides rewrites for bare specifiers like Polyserve or Zwitterion.
The following examples are written with Polymer. It shouldn't be too hard to adapt them to other libraries and frameworks, keeping in mind their data binding systems and DOM interactions. This documentation is outdated, using HTML Imports instead of ES Modules, and will be updated in the future:
At some point before you begin dispatching actions, you need to pass in your root reducer to any <redux-store></redux-store>
element through the root-reducer attribute. From the example:
<link rel="import" href="../../../lib/bower_components/polymer/polymer.html">
<link rel="import" href="../../../src/redux-store.html">
<link rel="import" href="../input-area/input-area.component.html">
<link rel="import" href="../text/text.component.html">
<dom-module id="test-app">
<template>
<redux-store root-reducer="[[rootReducer]]"></redux-store>
<test-input-area></test-input-area>
<test-text></test-text>
</template>
<script>
Polymer({
is: 'test-app',
ready: function() {
var initialState = {
temp: 'initial temp'
};
this.rootReducer = function(state, action) {
if (!state) {
return initialState;
}
switch(action.type) {
case 'CHANGE_TEMP': {
var newState = Object.assign({}, state);
newState.temp = action.newTemp;
return newState;
}
default: {
return state;
}
};
};
}
});
</script>
</dom-module>
If your component needs to listen to state changes, simply pop a <redux-store></redux-store>
element in and pass a listener function name in for the statechange
event. From the example:
<link rel="import" href="../../../lib/bower_components/polymer/polymer.html">
<link rel="import" href="../../../src/redux-store.html">
<dom-module id="test-text">
<template>
<redux-store on-statechange="mapStateToThis"></redux-store>
<div id="testText">Text from input above will go here</div>
</template>
<script>
Polymer({
is: 'test-text',
mapStateToThis: function(e) {
this.$.testText.innerHTML = e.detail.state.temp;
}
});
</script>
</dom-module>
To dispatch from within an element, first bind the action property of the element to the action property on <redux-store></redux-store>
. When you are ready to dispatch an action, set the action property on the element to the action that you want to dispatch. From the example:
<link rel="import" href="../../../src/redux-store.html">
<dom-module id="test-input-area">
<template>
<redux-store action="[[action]]"></redux-store>
<input id="testInput" type="text">
<button on-click="handleClick">Dispatch</button>
</template>
<script>
Polymer({
is: 'test-input-area',
handleClick: function(e) {
this.action = {
type: 'CHANGE_TEMP',
newTemp: this.$.testInput.value
};
}
});
</script>
</dom-module>
By default, there is one store for the entire application, meaning that each instance of a <redux-store></redux-store>
will use the same store. You can however use multiple stores if you've determined it is necessary for your application. Simply reference the store name as follows:
<redux-store root-reducer="[[rootReducer]]" store-name="fooStore"></redux-store>
<redux-store action="[[action]]" store-name="fooStore"></redux-store>
<redux-store on-statechange="mapStateToThis" store-name="fooStore"></redux-store>
<redux-store></redux-store>
before actions will be dispatched and state change events raised<redux-store></redux-store>
will use the same storestatechange
event supplies the redux state in the detail.state
property of the eventnpm install
npm run test-window