Using RxJS with filter(Boolean) for queries?
Yes, they are the same.
console.log(typeof Boolean); // prints function console.log(Boolean.prototype.constructor("truthy")); // prints true console.log(Boolean === Boolean.prototype.constructor); // prints true
The Boolean
global reference points to the constructor function which returns a boolean value from the first argument.
The constructor can be used to create a boolean wrapper object, but it is not the same as the primitive true value.
console.log(new Boolean("truthy")); // prints an object. console.log(new Boolean("truthy").valueOf() === true); // prints true console.log((new Boolean("truthy")) === true); // prints false console.log(Boolean("truthy") === true); // prints true
Reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean
They achieve the same result in that you don't get undefined values in your subscription.
The difference is that you lose Type Inference when using filter(Boolean)
const query = 'the query';of(query). pipe( filter(Boolean) ).subscribe(val); // val here is of type 'Any'of(query). pipe( filter(Boolean) ).subscribe((val: string)); // we can infer it back to string laterof(query). pipe( filter(v=> v!== undefined) ).subscribe(val); // val here is of type 'string'