Cleaner Null-Check Syntax

[DartBot]

This issue was originally filed by eiger...@gmail.com

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It would behoove Dart to adopt a cleaner syntax for null checking than the existing...

if (exampleVar != null) {
    exampleVar.doStuff();
}

Having PHP-like functionality would require altering the language spec on boolean values to null equating to false. This would allow the following:

if (exampleVar) {
    exampleVar.doStuff();
}

Another option that would not require adjusting the boolean value language spec is adding a groovy-like null-safe operator to the syntax:

exampleVar?.doStuff();

This is handy, but it would not allow making logically different decisions based on null status - something that may or may not be necessary.

Another option would be implementing the ? operator as a null-check in the parent Object class. Then, we could do...

if (exampleVar?) {
    exampleVar.doStuff();
}

There are other options, too - any of them that would reduce the syntax weight would be helpful.

[DartBot]

This comment was originally written by drfibonacci@google.com

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Issue #61 has been merged into this issue.

[DartBot]

This comment was originally written by drfibonacci@google.com

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Added Area-Language, Triaged labels.

[DartBot]

This comment was originally written by waqner...@gmail.com

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Issue #41 is somewhat redundant with this.

Also, issue #61 was about a replacement for || on objects.

In JS you can do

foo = bar || default; //default in case bar is falsy/null

While Dart cleans up the mess as to when an object is considered truthy, it renders the operator || unusable for null-checks and provides no nice alternative, like ?? in C#

foo = bar ?? default;

[gbracha]

If we resolve this, it will probably be done via something like the safe navigation operator, so I'm marking this as a duplicate.

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Added Duplicate label.
Marked as being merged into #41.

[dJani97]

Coming back from TypeScript to Dart, I really miss if statements that accepted nullable expressions.

if(someObject?.someField) looks a lot cleaner than if(someObject?.someField ?? false).