Incorrect JS number-to-string conversion for radices other than 10

[wilkinson]

Problem

The Number.prototype.toString method is not computing correct results (which are defined here as "the results returned by command-line debugging shells for JavaScriptCore, Spidermonkey, and V8 as well as the developer consoles inside Chrome, Firefox, and Safari").

Test cases

(0.001).toString(16)   // returns "0",  but should return "0.004189374bc6a7f"
(1.001).toString(16)   // returns "1",  but should return "1.004189374bc6a"
(-0.001).toString(16)  // returns "-0", but should return "-0.004189374bc6a7f"
(0.0005).toString(16)  // returns "0",  but should return "0.0020c49ba5e353f8"

Hypothesis

Somehow, this conversion is not being handled by JavaScriptCore like it should be, because these results are computed correctly in the command-line JSC debugging shell available on OS X and in the developer console in Safari.

[wilkinson]

I forgot to include a test case for a different base, but here's some more weirdness for you:

(0.001).toString(15)  // returns "0"

Firefox and Safari return "0.0035959595959596". Chrome returns "0.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".

I'm not sure why V8 goes crazy there, but according to page 48 of the ES5.1 specification, the correct result is definitely not "0".

[vitallium]

Please upgrade to PhantomJS 2.0. 1.9.x is no longer supported, and known to have many crasher bugs that are fixed in 2.0.