LEARNING JAVASCRIPT - Trang 84

2

Newlines after

return

statements will cause problems; see

Chapter 6

for more information.

funds

=

funds

-

1

;

// one step back

}

This

while

loop will eventually terminate: every time through the loop,

funds

increa‐

ses by two and decreases by one for a net of 1. Eventually,

funds

will be 100 and the

loop will terminate.
While it’s very common to use a block statement with control flow, it’s not required.

For example, if we wanted to simply count up to 100 by twos, we don’t need a block

statement:

let

funds

=

50

;

// starting conditions

while

(

funds

>

1

&&

funds

<

100

)

funds

=

funds

+

2

;

Whitespace

For the most part, JavaScript doesn’t care about additional whitespace (including

newlines

2

): 1 space is as good as 10, or 10 spaces and 10 newlines. This doesn’t mean

you should use whitespace capriciously. For example, the preceding

while

statement

is equivalent to:

while

(

funds

>

1

&&

funds

<

100

)

funds

=

funds

+

2

;

But this hardly makes it look as if the two statements are connected! Using this for‐

matting is very misleading, and should be avoided. The following equivalents, how‐

ever, are relatively common, and mostly unambiguous:

// no newline

while

(

funds

>

1

&&

funds

<

100

)

funds

=

funds

+

2

;

// no newline, block with one statement

while

(

funds

>

1

&&

funds

<

100

) {

funds

=

funds

+

2

; }

There are those who insist that control flow statement bodies—for the sake of consis‐

tency and clarity—should always be a block statement (even if they contain only one

statement). While I do not fall in this camp, I should point out that careless indenta‐

tion fuels the fire of this argument:

while

(

funds

>

1

&&

funds

<

100

)

funds

=

funds

+

2

;

funds

=

funds

-

1

;

60 | Chapter 4: Control Flow

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