rn-collie/proxy/Proxy.js

A UI library for react native.

import BaseInterceptor from "./BaseInterceptor";

export default class Proxy<T> {
    _instance: T = null;
    _currentFun: string = null;
    _isObject: boolean = true;

    constructor(instance: T) {
        this._instance = instance;
        Object.keys(instance).forEach((key) => {
            if (typeof instance[key] === 'function') {
                this[key] = function () {
                    instance[key](...arguments);
                }
            } else {
                this[key] = instance[key];
            }
        })
    }

    /**
     * 创建一个代理
     * @param object
     * @returns {Proxy}
     */
    static create(object: Object | Function) {
        let type = typeof object;
        if (type === 'object') {
            return new Proxy(object);
        } else {
            let proxy = new Proxy({
                next: object,
            });
            proxy._isObject = false;
            return proxy;
        }
    }

    /**
     * 执行最近被拦截的方法
     */
    next() {
        if (this._currentFun) {
            this[this._currentFun](...arguments);
        }
    }

    /**
     * 拦截具体的方法,可传多个拦截器,进行链式拦截
     * @param fun 需要拦截的方法名字或者拦截器,如果拦截的是对象,则此参数为被拦截的方法的名字,否则此参数为拦截器
     * @param interceptors 多个拦截器
     */
    intercept(fun?: string | BaseInterceptor, ...interceptors: Array<BaseInterceptor>) {
        let invokeFunStr;
        if (this._isObject) {
            if ((typeof fun) !== 'string') {
                throw new Error('proxy Object ,intercept first args need string')
            }
            invokeFunStr = fun;
        } else {
            interceptors = [fun, ...interceptors];
            invokeFunStr = 'next';
        }
        let thiz = this;
        this[invokeFunStr] = function () {
            let args = arguments;
            let realFun = thiz._instance[invokeFunStr];
            if (interceptors.length === 0) {
                realFun(...args);
            } else {
                thiz.exeInterceptor(0, interceptors, realFun, args);
            }

        };
        thiz._currentFun = invokeFunStr;
        return this;
    }

    exeInterceptor(index: number, interceptors: Array<BaseInterceptor>, fun: Function, args: Array<any>) {
        if (index < interceptors.length) {
            interceptors[index].handle(args).then((consume) => {
                if (index >= interceptors.length - 1) {
                    if (!consume) {
                        fun(...args);
                    }
                } else {
                    if (!consume) {
                        this.exeInterceptor(index + 1, interceptors, fun, args);
                    }
                }
            }).catch((e: Error) => {
                console.log("interceptor execute throw:" + e.message);
            });
        }
    }
}