Using Javascript logical OR operator as an default operator

Posted in Tutorials

The Javascript logical OR operator works like this …

If the first operand is truthy (see what is truthy and falsy), it will return the first operand.  Otherwise it will return the second operand.

So this code will output green…

because there is value passed into color making the first operand truthy.

However, this code will output blue (the default value if no color is passed) …

because “color” is undefined here.  And undefined is falsy.  So the second operand is returned.

 

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