value is a stringified integer in the smallest unit of
currency. For FLY, that means wei: 18 decimals of precision.
1 FLY = "1000000000000000000".The string format protects precision. Large FLY amounts exceed
JavaScript’s Number.MAX_SAFE_INTEGER. Treat value as a string
and convert with BigInt when you need to do math.
The published @flynetdev/core SDK ships
formatFly and formatUsdCents, the recommended way to turn wire values
into display strings. Both are exact and string-based, with no precision
loss.
If you’re not using the SDK, the hand-rolled equivalents below produce the
same results.
Chef’s warning - wei / 1e18 and Number(BigInt(wei) / BigInt(1e18)) both lose fractional FLY. The first silently rounds at ~16 significant digits; the second integer-truncates the fractional part entirely. Use one of the two correct approaches below.
JavaScript Number is IEEE-754 double-precision. Anything beyond ~2^53 significant digits loses bits. Fine for UI labels on amounts under ~9 quadrillion FLY; not fine for ledgering or comparisons.
Use the exact formatter for anything you’d round-trip back to wei, compare to thresholds, or sum across rows. Use the quick formatter only for fire-and-forget UI strings.
Where the API expresses a USD value, it uses an integer number of
cents, not the { value, currency } wire shape and not a floating-point
dollar amount. 1099 means $10.99. Integer cents avoid the rounding
errors of binary floating point, the same reasoning behind stringified FLY
wei. Format with formatUsdCents from the SDK:
import { formatUsdCents } from "@flynetdev/core";formatUsdCents(1099); // "10.99"formatUsdCents(500); // "5.00"
