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layout: post title: Javascript Default date: —

Javascript Default

*In JavaScript, parameters of functions default to undefined.

*However, in some situations it might be useful to set a different default value.

*This is where default parameters can help.

*In the past, the general strategy for setting defaults was to test parameter values in the body of the function,

• and assign a value if they are undefined. If in the following example,

• no value is provided for b in the call,

its value would be undefined when evaluating ab and the call to multiply would have returned NaN.

• However, this is caught with the second line in this example: