Different with JS behaviour for NaN || FloatValue

[MaxGraey]

JS/TS (expected):

NaN || 2.0 // -> 2.0
2.0 || NaN // -> 2.0
NaN && 2.0 // -> NaN
2.0 && NaN // -> NaN

AS (actual):

NaN || 2.0 // -> NaN
2.0 || NaN // -> 2.0
NaN && 2.0 // -> 2.0
2.0 && NaN // -> NaN

[jtenner]

So NaN is treated as truthy because it's not zero.

[MaxGraey]

Yeah, but should interpret as falsy.

[jtenner]

Could we have a truthy operator?

@operator.prefix("truthy")

Return a bool.

[MaxGraey]

No, but we have @operator.prefix("!"). Anyway f64/f32 is built-in and require fix this on compiler level

[dcodeIO]

Yeah, we should make it behave like in JS. Code location is in compiler.ts makeIsFalseish/makeIsTrueish, with the challenge here being that a check like (x == 0.0) | (x != x) needs a temporary local but there's no flow context to add one. Obvious alternative is to use a helper function Number.isTrue or so provided by stdlib.

[willemneal]

NaN in js is ("b"+ "a" + + "n" + "a" + "s").toLowerCase();