You can also specify a special case, called
default
, that will be used if no other case
matches. It is conventional (but not required) to put the default case last:
switch
(
totalBet
) {
case
7
:
totalBet
=
funds
;
break
;
case
13
:
funds
=
funds
-
1
;
// give 1 pence to charity!
case
11
:
totalBet
=
0
;
break
;
case
21
:
totalBet
=
21
;
break
;
default
:
console
.
log
(
"No superstition here!"
);
break
;
}
The
break
is unnecessary because no cases follow
default
, but always providing a
break
statement is a good habit to get into. Even if you’re using fall-through execu‐
tion, you should get into the habit of including
break
statements: you can always
replace a
break
statement with a comment to enable fall-through execution, but
omitting a
break
statement when it is correct can be a very difficult-to-locate defect.
The one exception to this rule of thumb is if you are using a
switch
statement inside
a function (see
), you can replace
break
statements with
return
statements
(because they immediately exit the function):
function
adjustBet
(
totalBet
,
funds
) {
switch
(
totalBet
) {
case
7
:
return
funds
;
case
13
:
return
0
;
default
:
return
totalBet
;
}
}
As usual, JavaScript doesn’t care how much whitespace you use, so it’s quite common
to put the
break
(or
return
) on the same line to make
switch
statements more
compact:
switch
(
totalBet
) {
case
7
:
totalBet
=
funds
;
break
;
case
11
:
totalBet
=
0
;
break
;
case
13
:
totalBet
=
0
;
break
;
case
21
:
totalBet
=
21
;
break
;
}
74 | Chapter 4: Control Flow
