CODEWITHSUNDEEP
dart
iDecode
iDecode

Reputation: 28906

How to pass common arguments in Dart?

Say, I have:

callback.orderBy('foo', reverse: true).localToThis();
callback.orderBy('foo', reverse: true);

You can see in both callbacks, I am passing same arguments, 

'foo', reverse: true

Is there any way I can make them something (a variable or a method) so that I can use something like this:

callback.orderBy(common).localToThis();
callback.orderBy(common);

Upvotes: 0

Views: 443

Answers (2)

jamesdlin
jamesdlin

Reputation: 89995

callback.orderBy('foo', reverse: true).localToThis();
callback.orderBy('foo', reverse: true);

If you're calling the same function with the same set of arguments, if the function has no side-effects, you might as well just save the result and avoid calling the function again.

If the function does have side-effects or if you want to call the function with only some of its arguments the same, you could use a partial function application to bind arguments:

final orderBy = () => callback.orderBy('foo', reverse: true);
orderBy().localToThis();
orderBy();

Upvotes: 1

f-person
f-person

Reputation: 329

You can create a class, containing fields you want to be common

class OrderConfiguration {
  final String orderBy;
  final bool reverse;

  OrderConfiguration(this.orderBy, {reverse = false});
}

and then accept an instance of OrderConfiguration as an argument to orderBy


But you can do this only for your own functions, for functions that weren't written by you, you could make a wrapper function. (May be this is a better option for your function too)

void orderCallback(callback) {
  callback.orderBy('foo', reverse: true);
}

or if orderBy returns a value

Type orderCallback(callback) {
  return callback.orderBy('foo', reverse: true);
}

Upvotes: 1

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