Question

I am trying to create a recursive function that will loop through a multidimensional object and test whether the key exists in a separate object. If the key does not exist I want to break the loop and return false, if all the keys exist I want to return true.

The problem I am having is that the function always seems to be returning true. Here is the code I am using:

var properties = {'global': {'structure' : {'body': {}}}};

var testExists = {'global': {'structure': {'test': 'value'}}};

if( ! this.exists(properties, testExists)) {
   console.log("DOESNT EXIST");
}


exists: function(destination, source) {
    var exists = true;

    check:
    for (var property in source) {

        if(destination[property]) {
            arguments.callee(destination[property], source[property]);
        }
        else
        {
            exists = false;
            break check;
        }
    }

    console.log(exists);

    return exists;
},

When I view the console to see the value of ‘exists’ I see two line the first false the second is true, so there must be an error with the recursion I am creating

Answer 1

Your problem seems to be that you don’t use the result of the recursively called function.

Also, you shouldn’t use arguments.callee, but a function name, and potentially check for the parameters to be objects before enumerating their properties. And you might want to check also for properties of destination that are not in the enumerated source.

Try this:

function equal(destination, source) {
    if (Object(destination)!==destination || Object(source)!==source)
        // at least one of them is a primitive value
        return destination == source; // maybe use strict equality === ?
    for (var prop in source)
        if (!(prop in destination) || !equal(source[prop], destination[prop]))
            return false;
    return true;
}