[React] Update State in React with Ramda's Evolve

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In this lesson we'll take a stateful React component and look at how we can refactor our setState calls to use an updater function and then leverage Ramda's evolvefunction to make our updater function a reusable utility that isn't tied to the React API.

//@flowimport React from 'react';
import {inc, dec, lensProp, over, evolve, multiply} from 'ramda';// Using Lense
const countLens = lensProp('count');
const increase = over(countLens, inc);
const decrease = over(countLens, dec);
const doubleCount = evolve({count: multiply(2)});export default class Counter extends React.Component { state = {
count: 0
}; increase = () => this.setState(increase); decrease = () => this.setState(decrease); double = () => this.setState(doubleCount); render() {
return (
<div>
<button onClick={this.increase}>+</button>
{this.state.count}
<button onClick={this.decrease}>-</button>
<button
disabled={this.state.count === 0}
onClick={this.double}
>*2</button>
</div>
);
}}