Rule for pointless assignments

[ChristophP]

I recently have to debug a lot of old code and had some need for an ESLint that tells me when an assignment is pointless. A code example:

let name = "someval"; // pointless assignment, the value is never used

if (someComplicatedCondition) {
  name = "if";
} else {
  name = "else";
}

The following code would not violate the rule

let name"; // no assignment

if (someComplicatedCondition) {
  name = "if";
} else {
  name = "else";
}

neither would this

let name = "someval"; // pointless assignment
console.log(name); // here's a read before the variable is reassigned, so it's not pointless

if (someComplicatedCondition) {
  name = "if";
} else {
  name = "else";
}

In this example, the first assignment to "someval" is pointless, because the variable name is reassignment below without being read anywhere.

So I found myself wanting a rule that finds cases of values being assigned without being read before they are reassigned.
I looked around a bit but couldn't find anything like this. Does anyone know if a rule like this exists? If not, would that be considered a good addition?

PS: Keep in mind the example above is quite obvious but the codebase I'm dealing with cases like these are less obvious.

[mdjermanovic]

So I found myself wanting a rule that finds cases of values being assigned without being read before they are reassigned.
I looked around a bit but couldn't find anything like this. Does anyone know if a rule like this exists? If not, would that be considered a good addition?

It currently doesn't exist in the core, but a proposal for this rule has been accepted (#17559) and we are already working on it in #17625.

[ChristophP]

That sounds fantastic. Thank you for the info :-)