Object Comparing: check if an object contains the whole other object

Question

I have two objects. Their structure looks a bit like this:

{
 education: [\"school\", \"institute\"],
 courses: [\"HTML\", \"JS\", \"CSS\"],
 Computer: {
            


        

Answer 1

JavaScript (in ES5) has two composite native types (I'm assuming you don't have any custom collections in your code, if you do - I assume they support the 'old' iteration protocol (having .length)

Here is an annotated sketch of a solution. I did not run this - it's there to get you an idea of how to implement this algorithm. Note that this enters an endless loop for back references (var a = {}; a.a =a}).

function sub(big,small){
    if(typeof big === "function") return small === big; // function reference equality.
    if(big.length){ // iterable, for example array, nodelist etc. (even string!)
        if(small.length > big.length) return false; // small is bigger!
        for(var i = 0; i < small.length; i++ ){
            if(!sub(big[i],small[i])){ // doesn't have a property
                return false;
            }
        }
        return true; // all properties are subproperties recursively
    }
    if(typeof big === "object" && big !== null){
        // I assume null is not a subset of an object, you may change this, it's conceptual
        if(typeof small !== "object" || small === null) return false; 
        for(var key in small){
            // I consider the prototype a part of the object, you may filter this with a 
            // hasOwnProperty check here.
            if(!sub(big[key],small[key])){ // doesn't have a property
                 return false;
            }
            return true;
        }
    }
    return big === small; // primitive value type equality
                          // , or ES7 value type equality, future compat ftw :P
}