Can I execute multiple statements with shorthand if && in Javascript? - Stack Overflow

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var foo = true;

function doThis() {alert("do this");}
function doThat() {alert("do that");}

// fine
if(foo) {
    doThis();
    doThat();
}

// fine
foo && (doThis());

// NO, syntax error
foo && (doThis(); doThat(););

Is this even possible? Or I should'v not done this at all?

var foo = true;

function doThis() {alert("do this");}
function doThat() {alert("do that");}

// fine
if(foo) {
    doThis();
    doThat();
}

// fine
foo && (doThis());

// NO, syntax error
foo && (doThis(); doThat(););

Is this even possible? Or I should'v not done this at all?

• javascript
• if-statement
• shorthand

Share Follow asked Apr 13, 2013 at 19:31 user1643156user1643156 4,5471111 gold badges4141 silver badges5959 bronze badges

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3 Answers 3

Sorted by: Reset to default 11

Yes, if you separate the functions with mas:

foo && (bar(), baz())

This is a terrible coding practice, but it's useful for minifying code, or the purposes of code golf.

if (foo) {
    bar();
    baz();
}

turns into:

foo&&(bar(),baz())

and

if (!foo) {
    bar();
    baz();
}

turns into:

foo||(bar(),baz())

and

if (foo) {
    bar();
    baz();
} else {
    fizz();
    buzz();
}

turns into:

foo?(bar(),baz()):(fizz(),buzz())

although the variables would likely be renamed in a minifier to something like:

a&&(b(),c())

You can't put a semicolon in the middle of an expression.

foo && (doThis() || doThat());

As doThis has no return value, it evaluates as follows:

true && (doThis() || doThat());
(doThis() || doThat());
(undefined || doThat());
(doThat());
undefined;

But as answered by @zzzzBov, the ma operator can also be used and it is better in the sense that it doesn't depend on return values.

Note that such shorthands are not very readable, you should let minification tools do that kind of work. (e.g. Closure Compiler)

You can use the ma operator:

foo && (doThis(), doThat());

Of course if doThis returns a truthy value you can also have:

foo && doThis() && doThat();

But it's more like;

if (foo)
    if (doThis())
        doThat();

However usually this "shorthand" are not used if there is no assignment on the left, because makes the code uglier and less readable.

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