if-diff/compare.js

Alternative to Polymer's dom-if that allows comparing two properties rather than just binding to a single boolean property

//from https://gist.github.com/nicbell/6081098
export function compare(obj1, obj2) {
    if (Array.isArray(obj1) && Array.isArray(obj2)) {
        const obj1Length = obj1.length;
        if (obj1Length !== obj2.length)
            return false;
        for (let i = 0, ii = obj1Length; i < ii; i++) {
            if (!compare(obj1[i], obj2[i]))
                return false;
        }
        return true;
    }
    //Loop through properties in object 1
    for (const p in obj1) {
        //Check property exists on both objects
        if (obj1.hasOwnProperty(p) !== obj2.hasOwnProperty(p))
            return false;
        switch (typeof (obj1[p])) {
            //Deep compare objects
            case 'object':
                if (!compare(obj1[p], obj2[p]))
                    return false;
                break;
            //Compare function code
            case 'function':
                if (typeof (obj2[p]) == 'undefined' || (p != 'compare' && obj1[p].toString() != obj2[p].toString()))
                    return false;
                break;
            //Compare values
            default:
                if (obj1[p] != obj2[p])
                    return false;
        }
    }
    //Check object 2 for any extra properties
    for (var p in obj2) {
        if (typeof (obj1[p]) == 'undefined')
            return false;
    }
    return true;
}
;