The function
keyword can be used to define a function inside an expression.
function [name]([param1[, param2[, ..., paramN]]]) { statements }
name
paramN
statements
A function expression is very similar to and has almost the same syntax as a function statement (see function statement for details). The main difference between a function expression and a function statement is the function name, which can be omitted in function expressions to create anonymous functions. See also the chapter about functions for more information.
The following example defines an unnamed function and assigns it to x
. The function returns the square of its argument:
var x = function(y) { return y * y; };
If you want to refer to the current function inside the function body, you need to create a named function expression. This name is then local only to the function body (scope). This also avoids using the non-standard arguments.callee
property.
var math = { 'factorial': function factorial(n) { if (n <= 1) return 1; return n * factorial(n - 1); } };
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