javascript 使用 Jest 时使节点缓存无效
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Invalidate node cache when using Jest
提问by Tomasz Mularczyk
I have a file with object that gets populated with process.envproperties:
我有一个包含对象的文件，该文件填充了process.env属性：
env.js
环境.js
console.log('LOADING env.js');
const {
PROXY_PREFIX = '/api/',
USE_PROXY = 'true',
APP_PORT = '8080',
API_URL = 'https://api.address.com/',
NODE_ENV = 'production',
} = process.env;
const ENV = {
PROXY_PREFIX,
USE_PROXY,
APP_PORT,
API_URL,
NODE_ENV,
};
module.exports.ENV = ENV;
Now I try to test this file with different process.envproperties:
现在我尝试用不同的process.env属性测试这个文件：
env.test.js
环境测试.js
const envFilePath = '../../config/env';
describe('environmental variables', () => {
const OLD_ENV = process.env;
beforeEach(() => {
process.env = { ...OLD_ENV };
delete process.env.NODE_ENV;
});
afterEach(() => {
process.env = OLD_ENV;
});
test('have default values', () => {
const { ENV } = require(envFilePath);
expect(ENV).toMatchSnapshot();
});
test('are string values (to avoid casting errors)', () => {
const { ENV } = require(envFilePath);
Object.values(ENV).forEach(val => expect(typeof val).toEqual('string'));
});
test('will receive process.env variables', () => {
process.env.NODE_ENV = 'dev';
process.env.PROXY_PREFIX = '/new-prefix/';
process.env.API_URL = 'https://new-api.com/';
process.env.APP_PORT = '7080';
process.env.USE_PROXY = 'false';
const { ENV } = require(envFilePath);
expect(ENV.NODE_ENV).toEqual('dev');
expect(ENV.PROXY_PREFIX).toEqual('/new-prefix/');
expect(ENV.API_URL).toEqual('https://new-api.com/');
expect(ENV.APP_PORT).toEqual('7080');
expect(ENV.USE_PROXY).toEqual('false');
});
});
Unfortunately, even though I try to load the file in every test separately the file gets loaded only once, making the third test fail with:
不幸的是，即使我尝试在每个测试中单独加载文件，文件也只加载一次，使第三个测试失败：
Expected value to equal: "dev" Received: "production"
Expected value to equal: "dev" Received: "production"
P.S. It doesn't fail when I run the test alone.
PS 当我单独运行测试时它不会失败。
I also know that env.jsloads only once because console.log('LOADING env.js');gets fired only once.
我也知道env.js只加载一次，因为console.log('LOADING env.js');只被触发一次。
I tried to invalidate Nodes cache like:
我试图使节点缓存无效，例如：
beforeEach(() => {
delete require.cache[require.resolve(envFilePath)];
process.env = { ...OLD_ENV };
delete process.env.NODE_ENV;
});
but require.cacheis empty {}before each test so it seems that Jestis somehow responsible for importing the file.
但在每次测试之前require.cache都是空的{}，所以似乎Jest以某种方式负责导入文件。
I also tried to run yarn jest --no-cachebut didn't help.
我也试图逃跑，yarn jest --no-cache但没有帮助。
So what I want is to load env.jsbefore each test so I can test how it behaves with different node environmental variables.
所以我想要的是在每次测试之前加载env.js以便我可以测试它在不同节点环境变量下的行为。
jest@^22.0.4
开玩笑@^22.0.4
回答by Prakash Sharma
You can use jest.resetModules()in beforeEachmethod to reset the already required modules
您可以使用jest.resetModules()inbeforeEach方法重置已经需要的模块
beforeEach(() => {
jest.resetModules()
process.env = { ...OLD_ENV };
delete process.env.NODE_ENV;
});
