[removed] Comparing two float values

Question

I have this JavaScript function:

Contrl.prototype.EvaluateStatement = function(acVal, cfVal) {

    var cv = parseFloat(cfVal).toFixed(2);
    var av = parse         


        

Answer 1

Comparing floats using short notation, also accepts floats as strings and integers:

var floatOne = 2, floatTwo = '1.456';

Math.floor(floatOne*100) > Math.floor(floatTwo*100) 

(!) Note: Comparison happens using integers. What actually happens behind the scenes: 200 > 145

Extend 100 with zero's for more decimal precision. For example use 1000 for 3 decimals precision.

Test:

var floatOne = 2, floatTwo = '1.456';
console.log(Math.floor(floatOne*100), '>', Math.floor(floatTwo*100), '=', Math.floor(floatOne*100) > Math.floor(floatTwo*100));

Answer 2

The Math.fround() function returns the nearest 32-bit single precision float representation of a Number.

And therefore is one of the best choices to compare 2 floats.

if (Math.fround(1.5) < Math.fround(1.6)) {
    console.log('yes')
} else {
    console.log('no')
}

>>> yes

// More examples:
console.log(Math.fround(0.9) < Math.fround(1));                            >>> true
console.log(Math.fround(1.5) < Math.fround(1.6));                          >>> true
console.log(Math.fround(0.005) < Math.fround(0.00006));                    >>> false
console.log(Math.fround(0.00000000009) < Math.fround(0.0000000000000009)); >>> false

Answer 3

Compare float numbers with precision:

var precision = 0.001;

if (Math.abs(n1 - n2) <= precision) {
  // equal
}
else {
  // not equal
}

UPD: Or, if one of the numbers is precise, compare precision with the relative error

var absoluteError = (Math.abs(nApprox - nExact)),
  relativeError = absoluteError / nExact;

return (relativeError <= precision);

Answer 4

toFixed returns a string, and you are comparing the two resulting strings. Lexically, the 1 in 12 comes before the 7 so 12 < 7.

I guess you want to compare something like:

(Math.round(parseFloat(acVal)*100)/100)

which rounds to two decimals