Can you explain why this code snippet is successful:
exports.foo = 'foo';
var bar = require('./foo');
console.log(bar); // {foo: 'foo'}
While this one fails to produce the desired output:
var data = { foo: 'foo' };
exports = data;
var bar = require('./foo');
console.log(bar); // {}
// expected {foo: 'foo'}
Allow me to tackle this as a JavaScript question Here is a snippet of code for demonstration:
function a() {}
a.prototype.foo = {test:"bar"}
var d = new a();
var c = new a();
console.log(d.prototype ==== c.prototype) // Both c and d share the same prototype object
d.foo.hai = "hello"
console.log(d.prototype ==== c.prototype) // Still they refer to the same
d.foo = {im: "sorry"}
console.log(d.prototype ==== c.prototype) // now they don't
The scenario is similar when working with Node.js
console.log(module.exports === exports);// true; They refer to the same object
exports.a = {tamil: "selvan"}
console.log(module.exports === exports);// true even now
exports = {sorry: "im leaving"}; // overrides modules.exports
console.log(module.exports === exports); //false now they don't
console.log(module.exports); // {a: {tamil: "selvan"}}
console.log(exports); // {sorry: "im leaving"}
Remember, exports and module.exports point to the same core object until overridden like with JavaScript's prototype object. The reference changes upon override.
module.exports = {something: "works"}Even in the above example,
module.exports === exports //is false they are no more the sameThis demonstrates the vice versa concept too :)
Another important note: module serves as the current module reference, so it is advisable to utilize module.exports over exports
To correct the second code snippet, simply change exports = data; to module.exports = data;.
The reason why the initial version doesn't function as intended is because it merely assigns another object to the variable exports within the module's namespace. On the other hand, the latter option updates the value of the exports property on the module object with the contents of your data object.
It seems that in the second code snippet, you are essentially replacing the export object. Consequently, if your code were to work as intended, it is likely that all previous exports would be erased or replaced by this new one. It's possible that Node.js has some safeguards in place to prevent this from happening and maintain the integrity of its modules.
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