lib/block.js
function (obj, other) {
    var notIn = {};
    for (var key in obj) {
        if (other[key] === undefined) {
            notIn[key] = true;
        }
    }
    return _.keys(notIn);
}
function (obj, other) {
    var notIn = {};
    for (var key in obj) {
        if (other[key] === undefined) {
            notIn[key] = true;
        }
    }
    return _.keys(notIn);
}
function ( obj , other ) { var notIn = { } ; for ( var key in obj ) { if ( other [ key ] === undefined ) { notIn [ key ] = true ; } } return _ . keys ( notIn ) ; }
Find keys that exist in the specified object that don't exist
in the other object.
Find keys that exist in the specified object that don t exist in the other object .