What is the best way to simulate protected variables in javascript?
class Parent{
#variable; // Private variable. This is not to be public.
constructor(value)
{
this.#variable = value;
}
}
class Child extends Parent{
getNewVariable()
{
return (1 + this.#variable); // Uncaught SyntaxError: Private field '#variable' must be declared in an enclosing class
// We want #variable to be accessible without making it public.
}
}
Since javascript doesn't support protected variables yet,
What is the best option for accessing private variables from superclasses in extended classes?
I haven't been able to find much documentation on this, so any suggestions would be very helpful.
+++ late answer, but here we go ... +++
A WeakMap based approach most probably covers what the OP is looking for ...
const protectedStatesMap = new WeakMap;
class Parent{
constructor(foo) {
protectedStatesMap.set(this, { foo });
}
getFoo() {
return protectedStatesMap.get(this).foo;
}
}
class Child extends Parent{
constructor(foo, bar) {
super(foo);
Object.assign(protectedStatesMap.get(this), { bar })
}
getBar() {
return protectedStatesMap.get(this).bar;
}
}
const childA = new Child('foo', 'bar');
const childB = new Child('baz', 'biz');
console.log('childA.getFoo() ...', childA.getFoo());
console.log('childA.getBar() ...', childA.getBar());
console.log('childB.getFoo() ...', childB.getFoo());
console.log('childB.getBar() ...', childB.getBar());.as-console-wrapper { min-height: 100%!important; top: 0; }