如何防止在NodeJS中生成模块？

Question

根据问题标题，我有一个只应该在测试中使用的模块，如何防止它在生产中使用？

Answer 1

Looks like you are trying to mock some modules in NodeJS for test cases.

Instead of importing conditionally, a better way would be to export real or mock object conditionally.

import mockModule from './mockModule';
import realModule from './realModule';

const exported = (CONDITION) ? mockModule : realModule;
export default exported;

Also, instead of mockModule you may wish to export some empty object for your use case. Something like:

const exported = (CONDITION)? {} : realModule;

CONDITION to check if the test is running could be different based on some environment variable or your test suite. Eg for mocha you can use:

var isInTest = typeof global.it === 'function';

Source: How to detect if a mocha test is running in node.js?

Also, with require you can import modules conditionally:

if (CONDITION) {
    const foo = require('foo');
}

Answer 2

It will be all down to your build process and environment variables. I know for example that if you build using Wepback then in your webpack.config file you have the following code which you can add an exclusion to:

module: {
    rules: [
        { test: /\.ts$/, loader: "ts-loader", exclude: /*myModuleToExclude*/, },
    ]
}

Just look for the specific implementation for your specific build process.

Answer 3

不要添加“依赖项”，而是在package.json的“devDependencies”部分添加模块