Name
Arguments.length — the number of arguments passed to a function
Synopsis
arguments
.
length
Description
The length
property of the
Arguments object specifies the number of arguments passed to the
current function. This property is defined only within a function
body.
Note that this property specifies the number of arguments
actually passed, not the number expected. See Function.length for the number of declared
arguments. Note also that this property does not have any of the
special behavior of the Array.length
property.
Example
// Use an Arguments object to check that correct # of args were passed
function
check
(
args
)
{
var
actual
=
args
.
length
;
// The actual number of arguments
var
expected
=
args
.
callee
.
length
;
// The expected number of arguments
if
(
actual
!=
expected
)
{
// Throw exception if they don't match
throw
new
Error
(
"Wrong number of arguments: expected: "
+
expected
+
"; actually passed "
+
actual
);
}
}
// A function that demonstrates how to use the function above
function
f
(
x
,
y
,
z
)
{
check
(
arguments
);
// Check for correct number of arguments
return
x
+
y
+
z
;
// Now do the rest of the function normally
}
See Also
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