[React] Update Component State in React With Ramda Lenses
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了[React] Update Component State in React With Ramda Lenses，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含2326字，纯文字阅读大概需要4分钟。
内容图文
In this lesson, we‘ll refactor a React component to use Ramda lenses to update our component state. We‘ll create a lens to focus on the property we want to target and use over to apply the existing state value to a utility function and we‘ll get back a new state that will be reflected in our rendered UI.
We have code here, and we are going to improve the code:
//
@flow
import React from ‘react‘;
import {inc, dec} from ‘ramda‘;
export default class Counter extends React.Component {
state = {
count: 0
};
increase = () => {
this.setState((prevState) => {
return {
count: inc(prevState.count)
};
})
};
decrease = () => {
this.setState((prevState) => {
return {
count: dec(prevState.count)
}
})
};
render() {
return (
<div>
<button onClick={this.increase}>+</button>
{this.state.count}
<button onClick={this.decrease}>-</button>
</div>
);
}
}
First, we can use Ramda lense to update code, if the component‘s state contains only one prop, it is ideal to use lense to create reusable method:
import {inc, dec, lensProp, over} from ‘ramda‘;
// Using Lense
const countLens = lensProp(‘count‘);
export default class Counter extends React.Component {
state = {
count: 0
};
increase = () => this.setState(
(prevState) => over(countLens, inc, prevState)
);
decrease = () => this.setState(
(prevState) => over(countLens, dec, prevState)
);
Because Ramda‘s method are auto currying, so we can write like:
increase = () => this.setState(over(countLens, inc)); decrease = () => this.setState(over(countLens, dec));
Second, it is recommended to pull out busniess logic out of component, so we can do:
//
@flow
import React from ‘react‘;
import {inc, dec, lensProp, over} from ‘ramda‘;
// Using Lense
const countLens = lensProp(‘count‘);
const increase = over(countLens, inc);
const decrease = over(countLens, dec);
export default class Counter extends React.Component {
state = {
count: 0
};
increase = () => this.setState(increase);
decrease = () => this.setState(decrease);
render() {
return (
<div>
<button onClick={this.increase}>+</button>
{this.state.count}
<button onClick={this.decrease}>-</button>
</div>
);
}
}
原文：http://www.cnblogs.com/Answer1215/p/6741675.html
内容总结
以上是互联网集市为您收集整理的[React] Update Component State in React With Ramda Lenses全部内容，希望文章能够帮你解决[React] Update Component State in React With Ramda Lenses所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。