Your Code (Including Comments) Takes up Runtime Memory

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Your Node.js Code (Including Comments) Takes up Runtime Memory

In the Node example below, we are logging the heapUsed property that's returned from process.memoryUsage(), and we divide this value by 1000, giving us the amount of allotted memory heap in kilobytes that we used to run this process.

console.log(`${process.memoryUsage().heapUsed / 1000}kb`)

// output: 2994.304kb

If we add a comment before the console log, we can see the heapUsed value go up. Our code, including comments, has an effect on memory used during the process.

//12345
console.log(`${process.memoryUsage().heapUsed / 1000}kb`)

// output: 2994.312kb

It's a little more interesting than that, though. If we add one more character, nothing changes:

//123456
console.log(`${process.memoryUsage().heapUsed / 1000}kb`)

// output: 2994.312kb

Why is that?

Well, it seems that, for every eight characters in our code, we need to allot another 8 bytes of heap memory.

In the comment above, we had reached this tipping point with //12345. With the additional character added in //123456, we're now dipping into memory that was already allotted, and so Node doesn't need to allot any more memory for this extra character.

If we append a string of 8 characters to //12345, we can see our heap usage allot an additional 8 bytes once again.

//1234512345678
console.log(`${process.memoryUsage().heapUsed / 1000}kb`)

// output: 2994.32kb

We've reached another tipping point, and Node had to allot more memory. If we remove just one character, Node again doesn't need the additional 8 bytes.

//123451234567
console.log(`${process.memoryUsage().heapUsed / 1000}kb`)

// output: 2994.312kb

This probably won't matter for a lot of cases, but it goes to show that minification and getting rid of commented out "code graveyards" can help reduce package size as well as improve memory usage.