siyu_app/common/ChainItem.js

// 定义链的某一项
function ChainItem(fn) {
    this.fn = fn;
    this.next = null;
}

ChainItem.prototype = {
    constructor: ChainItem,
    
    // 设置下一项
    setNext: function(next) {
        this.next = next;
        return next;
    },
    
    // 开始执行
    start: function() {
        return this.fn.apply(this, arguments);
    },
    
    // 转到链的下一项执行
    toNext: function() {
        if (this.next) {
           return this.start.apply(this.next, arguments);
        } else {
			return Promise.reject("无匹配的执行项目");
            // console.log('无匹配的执行项目');
        }
    }
};

export default ChainItem;