What is @babel/plugin-proposal-private-property-in-object?
The @babel/plugin-proposal-private-property-in-object package is a Babel plugin that allows developers to use the `#private in object` syntax to check for the existence of a private property within an object. This is part of a proposal for ECMAScript and is not yet part of the official language specification. The plugin transforms this syntax into a form that can be understood by current JavaScript engines.
Private property existence checks
This feature allows developers to check if a private field exists in an instance of a class. The code sample demonstrates how to define a private field and then check for its existence using the `in` operator.
class MyClass {
#myPrivateField;
hasPrivateField(obj) {
return #myPrivateField in obj;
}
}