Dart does support operator overloading using the operator keyword followed by the operator you want to overload. The following example overloads the == operator for the MyClass object:

class MyClass {  operator ==(MyClass other) {    // compare this to other  }}

almost all Darts built-in operators can be overloaded with a few notable exceptions being the assignment operator = and reference equivalence operator === (doesn't exist anymore).

As for the advantage of operator overloading, it allows you to reuse operators that have a well known semantic meaning such as == or + for operations on your objects. For example, if you have a Matrix class that overloads the + operator then you can add two matrices using the syntax m1 + m2 instead of the more cumbersome m1.plus(m2)

The chosen answer is no longer valid when you try overloads using the == operator in the new version. Now you need to do this:

class MyClass {  @override  bool operator ==(other) {    // compare this to other  }}

But it's not safe. other is not specified as a type, Something unexpected may happened. For example:

void main() {  var a = A(1);  var b = B(1);  var result = a == b;  print(result); //result is true}class A {  A(this.index);  final int index;  @override  bool operator ==(other) => other.index == index;}class B {  B(this.index);  final int index;}

So you could do like this:

class A {  A(this.index);  final int index;  @override  bool operator ==(covariant A other) => other.index == index;}

You need to use covariant. Because Object overloads the == operator.

or you can

Test Object Type:
visit: hash_and_equals

class A {  A(this.index);  final int index;  @override  bool operator ==(other) => other is A && (other.index == index);  @override  int get hashCode => index;}

To extend Lars' answer, you can also overload operators using the inline function syntax.

class MyClass {  operator ==(MyClass o) => id == o.id;}