What does the number mean?
const x = 500 tells a reviewer little. Is it a quantity, a price or a duration? Naming is part of making the decision understandable.
const unitPriceCents = 500;
const quantity = 3;
const subtotalCents = unitPriceCents * quantity;
const hasFreeDelivery = subtotalCents >= 10000;
console.assert(subtotalCents === 1500);
console.assert(hasFreeDelivery === false);
Units in a name prevent confusing cents with whole currency units. Boolean names should read like a question or statement: hasFreeDelivery, isEligible, canCollect. Functions usually name an action or question; arrays usually use plural names.
Guided review
Names such as data2 or calc conceal purpose. But short names are not automatically bad: a conventional index i in a very small loop may be clear. Choose enough context to disambiguate the value, not the longest possible name.
Do not name a subtotal totalWithTax if tax has not been added. Misleading precision is worse than a name that honestly describes the current value.
Independent exercise
Rename amount, result and flag in a routine that computes a discount from a subtotal and checks eligibility. State the units and whether result means the discount amount or the discounted subtotal.
Correction
Possible names include subtotalCents, discountCents and isEligibleForDiscount. If the result is after the deduction, discountedSubtotalCents is more accurate. There is no single required spelling; another reader should infer the value's role correctly.
Review
Read your function aloud using its names. If you must repeatedly explain "this is actually...", revise the vocabulary or the model. Names should reflect confirmed business concepts rather than obscure them behind technical abbreviations.