Example
mut d: double = 1e400;// ERROR: 1e400 overflows 'double's range and rounds to +inf‘double’ is an IEEE-754 double-precision float, which can represent roughly up to ~1.8 * 10^308. A literal bigger than that has no finite ‘double’ value to become, so Turf rejects it outright instead of silently handing you ‘inf’.
This is about the LITERAL itself – computing ‘inf’ at runtime (e.g. by dividing/multiplying variables) is still allowed and behaves as ordinary IEEE-754 floating point.
The fix is almost always a typo in the exponent, or the value genuinely doesn’t belong in a ‘double’.
Run turf --explain E078 in a terminal to read this again.