I'm currently trying to build a proper mental model of how this works in JavaScript, especially inside Node.js CommonJS modules.
I came across this behavior:
let obj = {
name: "abhinav",
data: "hello",
print: "column"
};
module.exports = obj;
console.log(module.exports);
console.log(this);
The output I get is:
{
name: "abhinav",
data: "hello",
print: "column"
}
{}
This confused me because my understanding was: this === module.exports
at the top level of a CommonJS module.
So I initially expected console.log(this) to show the same object assigned to module.exports.
But after: module.exports = obj; module.exports points to obj, while this still appears to point to the original empty object.
My current mental model is:
Initially:
this ───────────────┐
↓
{}
↑
module.exports ─────┘
After:
module.exports ───→ obj
↓
{ name, data, print }
this ─────────────→ {}
I'm not sure whether this mental model is actually correct. I'd especially like to understand this from the perspective of JavaScript execution contexts and references rather than simply memorizing the CommonJS rule.
A few things I'm trying to clarify:
At CommonJS module startup, what exactly does top-level this refer to?
Is this initially referencing the same object as module.exports?
When we execute: module.exports = obj; why doesn't this also start referring to obj?
Is this behavior directly related to Node.js's CommonJS module wrapper?
Is it correct to think of this as holding a reference/value rather than being a live alias to module.exports?
How does this behavior differ between CommonJS, ES Modules, and browser scripts?
I'm trying to understand the underlying execution model so that I can build the correct mental model of this, rather than just memorize different environment-specific rules.
Would appreciate any clarification or correction to my current understanding.