javascript - 有状态单例模块

Question

你能有一个有状态的 Node.js 模块吗？喜欢:

exports.connectionsCache = new (function () {
    var cache = {};

    this.getOrCreate = function (url) {
        if (!cache[url]) {
            cache[url] = new Connection(url);
        }
        return cache[url];
    };
}());

状态能否承受多次 require 调用？或者应该使用一个简单的全局对象来实现这一点？

Answer 1

require 已缓存该模块:

test2.js:

module.exports = {
    state: 0
};

测试.js

var state = require("./test2.js");

state.state = 3;

console.log(state.state);

var state2 = require("./test2.js");

console.log(state2.state);

state2.state = 4;

console.log(state.state);

输出

$ node test.js
3
3
4