if-diff/compare.ts

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: any, obj2: any) {
    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;
};