为什么我看到“define not defined”"使用RequireJS运行Mocha测试时？ [英] Why do I see "define not defined" when running a Mocha test with RequireJS?
问题描述
我试图了解如何开发独立的Javascript代码。我想编写带有测试和模块的Javscript代码，从命令行运行。所以我已经安装 node.js 和 npm 以及库 requirejs ，下划线， mocha 。
I am trying to understand how to develop stand-alone Javascript code. I want to write Javscript code with tests and modules, running from the command line. So I have installed node.js and npm along with the libraries requirejs, underscore, and mocha.
我的目录结构如下所示：
My directory structure looks like this:
> tree .
.
├── node_modules
├── src
│ └── utils.js
└── test
└── utils.js
其中 src / utils.js 是我的一个小模块使用以下代码撰写：
where src/utils.js is a little module that I am writing, with the following code:
> cat src/utils.js
define(['underscore'], function () {
"use strict";
if ('function' !== typeof Object.beget) {
Object.beget = function (o) {
var f = function () {
};
f.prototype = o;
return new f();
};
}
});
和 test / utils.js 是测试：
> cat test/utils.js
var requirejs = require('requirejs');
requirejs.config({nodeRequire: require});
requirejs(['../src/utils'], function(utils) {
suite('utils', function() {
test('should always work', function() {
assert.equal(1, 1);
})
})
});
然后我尝试从顶级目录运行（所以 mocha 看到测试目录）：
which I then try to run from the top level directory (so mocha sees the test directory):
> mocha
node.js:201
throw e; // process.nextTick error, or 'error' event on first tick
^
Error: Calling node's require("../src/utils") failed with error: ReferenceError: define is not defined
at /.../node_modules/requirejs/bin/r.js:2276:27
at Function.execCb (/.../node_modules/requirejs/bin/r.js:1872:25)
at execManager (/.../node_modules/requirejs/bin/r.js:541:31)
...
所以我的问题是：
- 这是构造代码的正确方法吗？
- 为什么我的测试没有运行？
- 学习这类东西的最佳方法是什么？我很难在谷歌找到好的例子。
谢谢......
[抱歉 - 暂时发布错误代码的结果;现在修复了]
[sorry - momentarily posted results from wrong code; fixed now]
PS我正在使用requirejs，因为我也希望稍后从浏览器运行此代码（或其中一些代码）。
PS I am using requirejs because I also want to run this code (or some of it) from a browser, later.
更新/解决方案
以下答案中没有的内容是我需要使用 mocha -u tdd 用于上面的测试样式。这是最终测试（也需要断言）及其使用：
Something that is not in the answers below is that I needed to use mocha -u tdd for the test style above. Here is the final test (which also requires assert) and its use:
> cat test/utils.js
var requirejs = require('requirejs');
requirejs.config({nodeRequire: require});
requirejs(['../src/utils', 'assert'], function(utils, assert) {
suite('utils', function() {
test('should always work', function() {
assert.equal(1, 1);
})
})
});
> mocha -u tdd
.
✔ 1 tests complete (1ms)
推荐答案
您的测试未运行的原因是因为 src / utils.js 不是有效的Node.js库。
The reason your test isn't running is because src/utils.js is not a valid Node.js library.
根据RequireJS文档，为了与Node.js和CommonJS require标准共存，你需要在您的 src / utils.js 文件的顶部添加一些样板文件，以便RequireJS的定义函数已加载。
According to the RequireJS documentation, in order to co-exist with Node.js and the CommonJS require standard, you need to add a bit of boilerplate to the top of your src/utils.js file so RequireJS's define function is loaded.
但是，由于RequireJS旨在能够要求经典面向Web浏览器的源代码，因此我倾向于使用以下模式：我想在浏览器中运行的Node.js库：
However, since RequireJS was designed to be able to require "classic" web browser-oriented source code, I tend to use the following pattern with my Node.js libraries that I also want running in the browser:
if(typeof require != 'undefined') {
// Require server-side-specific modules
}
// Insert code here
if(typeof module != 'undefined') {
module.exports = whateverImExporting;
}
这样做的好处是不需要为其他Node.js用户提供额外的库并且通常在客户端上与RequireJS一起使用。
This has the advantage of not requiring an extra library for other Node.js users and generally works well with RequireJS on the client.
一旦在Node.js中运行代码，就可以开始测试了。我个人仍然喜欢使用Expresso而不是mocha，即使它是后继测试框架。
Once you get your code running in Node.js, you can start testing. I personally still prefer expresso over mocha, even though its the successor test framework.
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