That's exactly what I do.

Why is a lot more important that what.

Here's an example I use (Verbatim from here[0]):

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Why Vs. What

I’ve come to realize that the most important inline documentation concerns WHY we are doing something; not WHAT we are doing. For example, no one wants to read “// Set the value of b to 3,” for a line of code that looks like let b = 3. That’s just dumb.

let b = 3 // Set the value of b to 3

However, they may want to know “// Set the value of b to the number of iterations we'll be making.”

let b = 3 // Set the value of b to the number of iterations we'll be making

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[0] https://medium.com/chrismarshallny/leaving-a-legacy-1c2ddb0c...