toPrecision method
Truncates this double to a given precision after the decimal point.
Unlike rounding, this always truncates towards zero.
precision: Number of decimal places to keep.
Example:
3.14159.toPrecision(2); // 3.14
3.149.toPrecision(2); // 3.14 (truncated, not rounded)
(-3.149).toPrecision(2); // -3.14
Implementation
double toPrecision(int precision) {
final num multiplier = pow(10, precision);
return (this * multiplier).truncate() / multiplier;
}