In Javascript, a top-level function expression is not allowed. For example,
function(){return 3;}will give a syntax error such as Unexpected token (. The work-around is to enclose the expression in parentheses:
(function(){return 3;})At least, in most environments this is a work-around. In JScript, both expressions are quietly ignored. No error message is given, and no return value results. In JScript, a more elaborate work-around is required:
[function(){return 3;}][0]or
0?0:function(){return 3;}... anything that includes the function expression as part of a wider expression will do.
At this point, one might be wondering why anyone would care. What's the use of a top-level expression anyway? In my case, the context was one that used eval. The contents of a Javascript file were being loaded and evaluated where the contract was for the file to contain a single anonymous function expression.
