Dunder methods being (unexhaustive list) : *__contains__, __delitem__,
__getitem__, __setitem__, __iter__ and __repr__* in my case.
Using javascript little-known 'Proxy object', and passing itself as the
target, it's possible to implement the equivalent of Leo's
SqlitePickleShare class!
*simple proof-of-concept below where it just mimics a dummy dict. Customize
as needed for other behaviors!*
Félix 🚀😊
class MyClass {
data = {};
constructor() {
return new Proxy(this, {
get(target, prop) {
prop = prop.toString();
console.log(`Getting property: ${prop}`);
if(prop==="toString"){
return target.toString.bind(target);
}
if(prop==='valueOf'){
return target.toString.bind(target);
}
if(prop==="Symbol(Symbol.iterator)"){
return target[Symbol.iterator].bind(target);
}
return target.data[prop];
},
set(target, prop, value) {
console.log(`Setting property: ${prop.toString()} to ${value}`);
target.data[prop] = value;
return true;
},
deleteProperty(target, prop) {
console.log(`Deleting property: ${prop.toString()}`);
delete target.data[prop.toString()];
return true;
},
has(target, prop) {
console.log(`Checking property presence: ${prop.toString()}`);
return prop in target.data;
},
});
}
valueOf() {
return 'running valueOf: ' + JSON.stringify(this.data);
}
toString() {
return 'running tostring:' + JSON.stringify(this.data);
}
*[Symbol.iterator]() {
for (const key in this.data) {
console.log('called iterator!');
yield [key, this.data[key]];
}
}
}
const obj = new MyClass();
obj['key'] = 'value'; // Setting property: key to value
console.log("testing setting and getting 'key'");
console.log(obj['key']); // Getting property: key, value
delete obj['key']; // Deleting property: key
console.log("deleted, should be false: ")
console.log('key' in obj); // Checking property presence: key, false
console.log("testing toString ")
obj['key3'] = 'value1';
obj['key4'] = 'value2';
console.log(obj.toString()); // {"key1":"value1","key2":"value2"}
console.log("testing Symbol.iterator");
for (const [key, value] of obj) {
console.log(`${key}: ${value}`);
}
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