Number.EPSILON

The Number.EPSILON property represents the difference between 1 and the smallest floating point number greater than 1.

You do not have to create a Number object to access this static property (use Number.EPSILON).

The EPSILON property has a value of approximately 2.2204460492503130808472633361816E-16, or 2-52.

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

if (Number.EPSILON === undefined) {
    Number.EPSILON = Math.pow(2, -52);
}

• The Number object it belongs to