Pointless Arithmetic

ID

javascript.pointless_arithmetic

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

JavaScript

Tags

code-smell, simplification

Description

Reports an arithmetic expression whose result is mathematically the same as one of its operands:

const a = x + 0;     // == x
const b = 0 + x;     // == x
const c = x - 0;     // == x
const d = x * 1;     // == x
const e = 1 * x;     // == x
const f = x / 1;     // == x

Rationale

These shapes are almost always typos: the developer meant a different operand or a different operator. Even when they are intentional (e.g. as a poor man’s numeric coercion), there are clearer JavaScript idioms — Number(x) or unary +x for coercion, parentheses for precedence — that document the intent.

The expression also adds a small but real cost: a reader has to confirm the arithmetic identity for every occurrence, every time.

Remediation

Drop the no-op operand:

const a = x;

If the goal is numeric coercion, switch to a self-documenting form:

const a = Number(x);   // explicit coercion
const a = +x;          // shorter, equivalent

Notes

The rule deliberately does not fire on:

  • x * 0 and 0 * x — sometimes used to coerce-then-zero an unknown value

  • 0 - x — equivalent to unary -x, a deliberate negation

  • 1 / x — the reciprocal, often the actual intent

BigInt forms (x + 0n, x * 1n, etc.) are detected through the same numeric-literal recognition.

References