How to initialize a variable inside an if condition?

Question

Is it possible to do something like the following? aka, initialize a variable inside an if statement condition?

Reasoning:
I have a network call that will fetch data, and I'd like to avoid the following options:

Calling it unless the first condition is false.
Calling it twice, once to fetch the data to check the conditional & once to use the data inside the condition
Having to nest if statements

So initializing the variable inside the conditional block seems like the cleanest solution.

if (condition1) {
  // Do something
} else if ( (String foo = await getBar()) == "not bar"){
  // Do something with foo
} else {
  // Fallback condition
}

mmcdon20 · Accepted Answer · 2022-11-29 17:22:38Z

3

One option would be to declare the variable before the condition like so:

String foo; // Declare variable here
if (condition1) {
  // Do something
} else if ((foo = await getBar()) == "not bar") {
  // Do something with foo
} else {
  // Fallback condition
}

answered Nov 29, 2022 at 17:22

mmcdon20

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Comments

Nik · Accepted Answer · 2025-10-15 04:09:41Z

0

You can use `if-case` now (as of dart 3.9.0):

if (false) {
    // do nothing
}
else if (Provider().getNewMessages() case final messages when messages.isNotEmpty) {
    print("${messages.length} messages found!");
} 
else {
    print("No messages found!");
}

edited Oct 15 at 4:09

answered Sep 14 at 7:18

Nik

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