26 lines
672 B
Markdown
26 lines
672 B
Markdown
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---
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tags:
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- node-js
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---
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# Module wrapping at runtime in NodeJS
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## The Module Wrapper Function
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When Node runs each of our module files are wrapped within an
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immediately-invoked function expression that has the following parameters:
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```js
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(function (exports, require, module, __filename, __dirname))
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```
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This is called the **module wrapper function**
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Note that one of these parameters is the
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[module object](Modules_in_NodeJS.md#structure-of-a-module).
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Within any module we can access these parameters: you can think of them as
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metadata about the module itself. `__filename` and `__dirname` are particularly
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useful when writing to files and modifying directories.
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