Floating point: why is 0.1 + 0.2 != 0.3?

0.1 + 0.2 === 0.3 is false in JavaScript. Is the language broken?

No — 0.1 and 0.2 have no exact binary representation, so the sum is 0.30000000000000004. Compare with a tolerance:

Math.abs(a - b) < Number.EPSILON

and use integers (cents) or a decimal library for money.