At a glance, it looks like the body of the
while
loop is executing two statements (two
steps forward and one step back), but because there’s no block statement here, Java‐
Script interprets this as:
while
(
funds
>
1
&&
funds
<
100
)
funds
=
funds
+
2
;
// while loop body
funds
=
funds
-
1
;
// after while loop
I side with those who say that omitting the block statement for single-line bodies is
acceptable, but of course you should always be responsible with indentation to make
your meaning clear. Also, if you’re working on a team or an open source project, you
should adhere to any style guides agreed upon by the team, regardless of your per‐
sonal preferences.
While there is disagreement on the issue of using blocks for single-statement bodies,
one syntactically valid choice is nearly universally reviled: mixing blocks and single
statements in the same
if
statement:
// don't do this
if
(
funds
>
1
) {
console
.
log
(
"There's money left!"
);
console
.
log
(
"That means keep playing!"
);
}
else
console
.
log
(
"I'm broke! Time to quit."
);
// or this
if
(
funds
>
1
)
console
.
log
(
"There's money left! Keep playing!"
);
else
{
console
.
log
(
"I'm broke"
!
);
console
.
log
(
"Time to quit."
)
}
Helper Functions
To follow along with the examples in this chapter, we’ll need two helper functions. We
haven’t learned about functions yet (or pseudorandom number generation), but we
will in upcoming chapters. For now, copy these two helper functions verbatim:
// returns a random integer in the range [m, n] (inclusive)
function
rand
(
m
,
n
) {
return
m
+
Math
.
floor
((
n
-
m
+
1
)
*
Math
.
random
());
}
// randomly returns a string representing one of the six
// Crown and Anchor faces
function
randFace
() {
return
[
"crown"
,
"anchor"
,
"heart"
,
"spade"
,
"club"
,
"diamond"
]
[
rand
(
0
,
5
)];
}
A Control Flow Primer | 61
