How would you high precision compare floats & doubles sent into QML functions from Cpp side?

Question

How would you compare floats & doubles sent into QML functions from Cpp side ?

If I want to do a high precision comparasion like below as mentioned here

bool AreSame(double a, double b) {
  return fabs(a - b) < EPSILON;
}

How should I do this in Qt QML ?

Or, Is it that it gets casted to real in QML & one need not worry about it?

Answer 1

You should do it the same as in JavaScript:

x = 0.2 + 0.1;
y = 0.3;
equal = Math.abs(x - y) < Number.EPSILON;

Please note that this value property is available since Qt 5.8. In previous Qt releases you can define your own epsilon, e.g. as:

readonly property double epsilon: Math.pow(2, -52)