description

# operator == method Null safety

bool operator == (

1. Object other

)

The equality operator.

The default behavior for all Objects is to return true if and only if `this` and `other` are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

- Total: It must return a boolean for all arguments. It should never throw or return `null`.

- Reflexive: For all objects `o`, `o == o` must be true.

- Symmetric: For all objects `o1` and `o2`, `o1 == o2` and `o2 == o1` must either both be true, or both be false.

- Transitive: For all objects `o1`, `o2`, and `o3`, if `o1 == o2` and `o2 == o3` are true, then `o1 == o3` must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator it should override the hashCode method as well to maintain consistency.

## Implementation

    bool operator ==(other) =>
        other is Rectangle &&
        left == other.left &&
        top == other.top &&
        width == other.width &&
        height == other.height;