Is Jest's ModuleNameMap a named export?

No, Jest's ModuleNameMapper is not a named export. It's a configuration option within Jest's configuration object, typically found in your jest.config.js or package.json file under the jest key.

Here's a breakdown:

1. What is ModuleNameMapper?

- ModuleNameMapper is a Jest configuration setting that allows you to map module paths to different locations. This is particularly useful when dealing with aliases, custom module paths, or when you want to mock certain modules during testing.

2. How to Use ModuleNameMapper:

- You configure ModuleNameMapper as a property within the moduleNameMapper object in your Jest configuration. It's an object where keys are regular expressions that match module paths, and values are the corresponding replacement paths.

3. Example Configuration:

// jest.config.js
module.exports = {
  moduleNameMapper: {
    '^@components/(.)$': '<rootDir>/src/components/$1',
    '^@utils/(.)$': '<rootDir>/src/utils/$1',
    '\\.(css|less|scss)$': 'identity-obj-proxy',
  },
};

4. Why it's not a Named Export:

- Jest's configuration is typically read from a configuration file, not imported as a module. Therefore, ModuleNameMapper is not something you import using JavaScript's import syntax. Instead, it's a property within the configuration object that Jest reads when it starts.

5. Key Takeaway:

- You don't import ModuleNameMapper; you configure it within your Jest configuration file. It's a setting, not a module or a named export.

In summary, ModuleNameMapper is a configuration option within Jest, not a named export. You configure it in your Jest configuration file to map module paths for your tests.

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