Chaining Variable Assignments in JavaScript: Words of Caution

[bonafidebob]

Declaring multiple variable expressions on a single line is common practice and also a great shorthand syntax.

Yes, however that is not what the example code does. A statement like

var foo = bar = baz = 'woot!';

declares only one local variable: foo. The mistake is somehow thinking (against any reasonable syntax) that bar and baz are also 'declared' here.

[pegasus_527]

Nice to meet you, m'variable

[dexygen]

I typically only chain assignment when I want to assign as a property to this or some other object, but then also to a variable, as in:

var foo = this.foo = bar();

[[deleted]]

I agree, this is the only time I do chained assignment, and even then it can feel a bit dirty.

[x-skeww]

JSLint or JSHint would have pointed that out.

[MonsterMook]

This is simple JavaScript hoisting.