react中装饰器的使用

利用装饰器简化代码，将表单验证操作统一到一个装饰器中进行

首先装饰器的定义为修饰器（Decorator）是一个函数，用来修改类的行为。
建立一个装饰器

export default (Comp) => {
   class Cp extends Comp{
     constructor(props){
            super(props);
            this.state = {
                ...this.state,
                errors: {

                },     
                 // error queuq
            this.errorQueue = {};
            }
            this.setEmailcode = this.setEmailcode.bind(this);
             this.callError = this.callError.bind(this);
            this.fIn = this.fIn.bind(this);
            this.bOut = this.bOut.bind(this);
                
    }
     setEmailcode(v){
            this._clearStateKey('emailcode', v);
            if(v.target.value.length < 7){
                this._changeHandler('emailcode', v);
            }
        }
        ckemailcode(){
        let rt = true;
             const errors = [];
             const KEY = 'gcode';
                const intl = this.intl

            this._isEmpty(this.state[KEY], errors, intl.formatMessage({id: "请输入谷歌验证码"}));
            //验证是否符合规则，不符合则扔到errors队列中去
            this._setError(KEY, errors);
        
            return this._hasError(KEY); 
        }
     _isEmpty(v, errors = [], msg = ''){
            !v && errors.push(msg);
            return !v;
        }
        _changeHandler(k, v){
            const target = v.target;
            const value = target.type === 'checkbox' ? target.checked : target.value;
            this.setState({
                [k]: value
            });
        }
         // flg is get code 1 is get code
        _setError(k, v, flg = 0){
            let { errors } = this.state,
            cd = this._isArray(v) && v.length;
       
            !this.errorQueue[k] && (this.errorQueue[k] = []);

            this.errorQueue[k][flg] = cd ? v : [];
            setTimeout(() => {
                this.setState(prevState => {
                    return {
                        errors: {
                            ...(prevState.errors),
                            [k]: cd ? (
                                errors[k] ? errors[k].unshift(...v) : errors[k] = [...v],
                                [...new Set(errors[k])]
                            ) : [...(this.errorQueue[k].filter(v => {
                                return v.length > 0;
                            })[0] || [])],
                        }
                    }
                });
            },0);
        }
        _hasError(k = ''){
           return !this.errorQueue[k].filter(v => v.length > 0).length;
        }
        callError(k, v){
            this._setError(k, v?[v]:[], 1);
            // keydown
            const KEY = 'ky' + k;
            if(this.state[KEY]){
                this.setState({
                    [KEY]: 0
                });
            }
        }

        clearsError(k = [], flg = 0){
            k.forEach(v => {
                this._setError(v, "",flg);
            });
            return new Promise((r,e) => {
                setTimeout(() => {
                    r(1);
                })
            })
        }
        
        changeImgCode() {
            let now = +new Date;
            this.props.changeImgCode(URL_IMG_CODE + "?t=" + now);
        }
        bOut(e){ 
            const k = this._getTgKey(e);
           if(this.state.focusBlu){
                this.setState({
                    focusBlu:''
                })
            }
           
            this.clearQueueKey(k);
            this.hasError([k]);
            this.Uc(k);
        }
         fIn(e){
            const key = this._getTgKey(e);
            key === 'password' && this.setState({
                mvInPwd: 1
            })
            this._setError(key, []);
            this._setError(key, [], 1);
        }

        _isEmpty(v, errors = [], msg = ''){
            !v && errors.push(msg);
            return !v;
        }
     return Cp;
}

在需要做表单验证的地方引入装饰器

import Form from '../../../decorator/form';
@Form
class WithdrawForm extends React.Component{
constructor(props){
        super(props)
        this.state = {
        emailcode : "",
}
this.setFoucs = this.setFoucs.bind(this)

}
 setFoucs(name){
    this.setState({
        focusBlu:name
    })
   }
renner(){
const {setEmailcode,bOut,fIn} = this
const {errors,ckFlg,emailcode} = this.state
const {emailcode:eemailcode = [] } = errors
return(

    

     {this.setCk();this.setFoucs('emailcode');this.fIn(e)}} onBlur={bOut} />
     
     {ckFlg ? eemailcode[0] : null}//错误提示信息

)
}
export default WithdrawForm