Dead stores refer to assignments made to local variables that are subsequently never used or immediately overwritten. Such assignments are
unnecessary and don’t contribute to the functionality or clarity of the code. They may even negatively impact performance. Removing them enhances code
cleanliness and readability. Even if the unnecessary operations do not do any harm in terms of the program’s correctness, they are - at best - a waste
of computing resources.
Exceptions
The rule ignores
- Initializations to
-1, 0, 1, undefined, [], {},
true, false and "".
- Variables that start with an underscore (e.g.
_unused) are ignored.
- Assignment of
null is ignored because it is sometimes used to help garbage collection
- Increment and decrement expressions are ignored because they are often used idiomatically instead of
x+1
- This rule also ignores variables declared with object destructuring using rest syntax (used to exclude some properties from object)
let {a, b, ...rest} = obj; // 'a' and 'b' are compliant
doSomething(rest);
let [x1, x2, x3] = arr; // 'x1' is noncompliant, as omitting syntax can be used: "let [, x2, x3] = arr;"
doSomething(x2, x3);
