I wish! Converting from double to int32 or uint32 in JS is far from a simple truncate or round, although it entails floor. From ECMA-262 5th Edition: 9.5 ToIn

I wish! Converting from double to int32 or uint32 in JS is far from a simple truncate or round, although it entails floor. From ECMA-262 5th Edition: 9.5 ToInt32: (Signed 32 Bit Integer) The abstract operation ToInt32 converts its argument to one of 2^32 integer values in the range −2^31 through 2^31−1, inclusive. This abstract operation functions as follows: 1. Let number be the result of calling ToNumber on the input argument. 2. If number is NaN, +0, −0, +∞, or −∞, return +0. 3. Let posInt be sign(number) * floor(abs(number)). 4. Let int32bit be posInt modulo 2^32; that is, a finite integer value k of Number type with positive sign and less than 2^32 in magnitude such that the mathematical difference of posInt and k is mathematically an integer multiple of 2^32. 5. If int32bit is greater than or equal to 2^31, return int32bit − 2^32, otherwise return int32bit. NOTE Given the above definition of ToInt32: • The ToInt32 abstract operation is idempotent: if applied to a result that it produced, the second application leaves that value unchanged. • ToInt32(ToUint32(x)) is equal to ToInt32(x) for all values of x. (It is to preserve this latter property that +∞ and −∞ are mapped to +0.) • ToInt32 maps −0 to +0. --- end snip --- Note that this path is rare in code that does not use shift or bitwise-logical operators or certain built-in functions. See https://bugzilla.mozilla.org/show_bug.cgi?id=597814 https://bugzilla.mozilla.org/show_bug.cgi?id=597814.