Split Variable

Removes smells

Symptom

A single variable (often named `temp`, `result`, `value`) reassigned multiple times to hold conceptually distinct values — perimeter, then area; current iteration result, then accumulator.

Goal

Each variable has one role; reassignment patterns reflect distinct purposes rather than reused storage.

Before the refactoring

let temp = 2 * (height + width);
console.log(temp);
temp = height * width;
console.log(temp);

After the refactoring

const perimeter = 2 * (height + width);
console.log(perimeter);
const area = height * width;
console.log(area);

Example source: Illustrative example written for this site, not a quotation from any source.

Pressure

The reader must track which role the variable currently holds; bugs hide where one role's update accidentally clobbers another; refactoring either use is impossible without disentangling.

Tradeoff

If the two uses were actually coupled — shared init or synchronized update — splitting them invites drift the single mutation kept in sync.

Relief

Names match purpose; the type system can narrow each role; refactoring each use becomes local.

Trap

Splitting variables whose uses were genuinely coupled — accumulator that depends on a previous-iteration version of itself — fragments coherent state into separate variables that have to re-establish the coupling.