javascript - When doing || operation between jquery objects, why is the returned value not of boolean type?

Question

jquery source code snippets are as follows:

        // HANDLE: $(expr, $(...))
        } else if ( !context || context.jquery ) {
            return ( context || rootjQuery ).find( selector );

I think context here is a jquery object, rootjquery is $(document)

But shouldn’t the demerit they return be a Boolean value? Why is it a jquery object here?

So what does the || operation do here? What is its role???

Thanks

Answer 1

Please see here for the basics, which is clear at a glance.
https://developer.mozilla.org...

One more thing, before ES2015, JS functions did not have default parameters.
In order to use default parameters like other languages, they were often written like this

function demo(arg){
    arg = arg || true;
}

In order to be compatible with different browser APIs, we often write like this.

if( !window.requestAnimationFrame ){
    window.requestAnimationFrame = (window.webkitRequestAnimationFrame ||
                                    window.mozRequestAnimationFrame ||
                                    window.msRequestAnimationFrame || 
                                    function (callback){
                                      return setTimeout(callback, 1000 / 60);
                                    });
}

Answer 2

Javascript logical operators can be used in non-Boolean environments.

Although the && and || operators can be used in non-Boolean environments, if their return values ​​can be converted to Boolean values, they can also be considered Boolean operations

(from logical operator)

For non-Boolean environments:

When there is one false, return the value on the false side
When there are two false, return the value before the operator (left side);
When there are two true, return the value after the operator (right side) value.

(derived from the return value of logical operations in JavaScript (logical AND &&, logical OR ||, logical NOT!))