Select keys from a javascript object using a regular expression. Returns an object containing only the keys that matched the expression in the original object.

js_obj_getter_by_reg.js

var keyMatch = function(o,r){

    var c  = 0;
    var nO = {};

    Object.keys(o).forEach(function(k){
        c++;
        no[k] = k.match(r) ? o[k] : void 0;
    });

    return ( ~c ? JSON.stringify(JSON.parse(nO)) : null );
};

var test = {
    abc: 'foo',
    acb: 'foo',
    bac: 'bar' 
};

keyMatch(test,/^a/);

// Returns
// ===============
// {
//     abc: 'foo',
//     acb: 'foo'
// }