JavaScript Array数组分页

/** * 分页数组 * @param array {@link Array}：源数组； * @param pn {@link Number}：当前页； * @param ps {@link Number}：页显示数； * @param fn {@link Function}：执行完成后回调； * @return {@link Page4array} * @constructor * @version V1.0.1 * @author Haining.Liu */
function Page4array(array, pn, ps, fn) { 
   
	for (let i = 1, len = arguments.length; i < len; i++) { 
   
		let pm = arguments[i];
		if (pm && typeof pm == 'function') { 
       //切换回调参数位置
			arguments[i] = undefined;
			fn = pm;
			break;
		}
	}
	this.fn = fn;
	this.source = array;
	this.total = 0; //总数
	this.size = 1;  //总页数
	if (array && array.length) { 
   
		this.total = array.length;
		ps = (!ps || ps < 0) ? 10 : Number(ps);
		if (ps > 0)
			this.size = Math.ceil(this.total / ps);
	}
	this.adjust(pn, ps);
	Object.prototype.toString.call(array) == '[object Array]' ? this.run() : (this.result = []);
	return this;
}

/** * 静态初始化函数 * @param array {@link Array}：源数组； * @param pn {@link Number}：当前页； * @param ps {@link Number}：页显示数； * @param fn {@link Function}：执行完成后回调； * @return {@link Page4array} * @constructor * @version V1.0.1 * @author Haining.Liu */
Page4array.Init = function () { 
   
	return new Page4array(...arguments);
};

(function () { 
   
	/** * 上一页 * @param fn {@link Function}：执行完成后回调； * @return {@link Page4array} */
	Page4array.prototype.prev = function (fn) { 
   
		this.pageNum--;
		return this.run(fn);
	};
	/** * 下一页 * @param fn {@link Function}：执行完成后回调； * @return {@link Page4array} */
	Page4array.prototype.next = function (fn) { 
   
		this.pageNum++;
		return this.run(fn);
	};
	/** * 去指定页 * @param pn {@link Number}：指定页； * @param fn {@link Function}：执行完成后回调； * @return {@link Page4array} */
	Page4array.prototype.to = function (pn, fn) { 
   
		this.adjust(pn);
		return this.run(fn);
	};
	/** * 执行 * @param fn {@link Function}：执行完成后回调； * @return {@link Page4array} */
	Page4array.prototype.run = function (fn) { 
   
		this.adjust();
		// this.start = (this.pageNum - 1) * this.pageSize;
/* if (this.start > this.total) { this.result = []; return this; }*/
		this.result = this.source.slice(this.start, this.end + 1);
		this.fn = fn || this.fn;
		if (!this.fn || typeof this.fn != 'function')
			this.data = undefined;
		else
			try { 
   
				this.data = this.fn(this.result, this);
			} catch (e) { 
   
				console.error(this.data = e);
			}
		return this;
	};
	/** * 分页值校准 * @param pn {@link Number}：当前页； * @param ps {@link Number}：页显示数； * @return {@link Page4array} */
	Page4array.prototype.adjust = function (pn, ps) { 
   
		this.pageNum = pn || this.pageNum;
		this.pageSize = ps || this.pageSize;
		this.pageSize = (!this.pageSize || this.pageSize < 0) ? 10 : Number(this.pageSize);
		this.pageNum = (!this.pageNum || this.pageNum <= 0) ? 1 :
				(this.pageNum > this.size) ? this.size : Number(this.pageNum);

		this.start = (this.pageNum - 1) * this.pageSize;
		this.end = (this.start + this.pageSize >= this.total) || this.pageSize == 0 ?
				this.total : this.start + this.pageSize;
		this.end--;
		return this;
	};
	/** * 重写toString * @return {@link String} */
	Page4array.prototype.toString = function () { 
   
		return JSON.stringify(this);
	};
})();

let ids = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
// ids = { //设置为错误Object类型，模仿Array
// length: 12
// };
// ids = null;

// let page = Page4array.Init(ids); //调用静态初始化函数，同 new Page4array(ids) 的写法
// console.log(page);
// console.log(page.prev());
// console.log(page.next(fn));
// console.log(page.next(null));
// page.fn = null; //将当前实例的回调置空
// console.log(page.prev());
for (let i = 0; i < 6; i++) { 
   
	console.log('\t========', i, '\r\n');
	console.log(Page4array.Init(ids, fn, 5));
	console.log(Page4array.Init(ids, i, 5, fn));
	console.log(Page4array.Init(ids, i, fn));
	console.log(Page4array.Init(ids, i, 15, fn));
}

/** * 模仿分页回调处理 * @param data {@link Array}：当前分页数组； * @return {@link Array} * @version V1.0.1 */
function fn(data) { 
   
	let rs = new Array(data.length);
	for (let i = 0; i < data.length; i++)
		rs[i] = { 
   id: data[i]};
	return rs;
}