Question

109

A javascript design pattern for options with default values?

rated 0 times [ 113] [ 4] / answers: 1 / hits: 40995 / 13 Years ago, wed, march 7, 2012, 12:00:00

// opt_options is optional

function foo(a, b, opt_options) {

  // opt_c, opt_d, and opt_e are read from 'opt_options', only c and d have defaults

  var opt_c = 'default_for_c';

  var opt_d = 'default_for_d';

  var opt_e; // e has no default



  if (opt_options) {

    opt_c = opt_options.c || opt_c;

    opt_d = opt_options.d || opt_d;

    opt_e = opt_options.e;

  }

}

The above seems awfully verbose. What's a better way to handle argument options with default parameters?

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raymondorlandok

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1 Year ago

answered 13 Years ago ravenl · Accepted Answer

Now that I think about it, I kind of like this:

function foo(a, b, opt_options) {

  // Force opt_options to be an object

  opt_options = opt_options || {};



  // opt_c, opt_d, and opt_e are read from 'opt_options', only c and d have defaults

  var opt_c = 'default_for_c' || opt_options.c;

  var opt_d = 'default_for_d' || opt_options.d;

  var opt_e = opt_options.e; // e has no default

}