Array lengthening methods applied to maximally long arrays

James Graham jgraham at
Wed May 13 02:14:39 PDT 2009

As far as I can tell, the ES5-specified behavior of

a = new Array()
a.length = Math.pow(2,32)-1

is to create a non-array-index property of the array with name 
4294967296 (i.e. 2^32) and value 1 before throwing a RangeError hen 
trying to update the length. However this property isn't created in the 
majority of implementations (at least it doesn't happen in my builds of 
Spidermonkey, V8 and Squirrelfish) and since it is rather surprising 
that the operation would, in some sense, succeed before throwing an 
error, it seems like it might be nice to change this part of the spec to 
reflect the implementations.

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