How to deeply map object keys with JavaScript (lodash)?

Question

https://lodash.com/docs#mapKeys

Is it possible to map an Object\'s keys deeply using Lodash? If not, is there another library providing this functionality (if grouped wi

Answer 1

Here's how you can do that in lodash:

_.mixin({
    'deepMapKeys': function (obj, fn) {

        var x = {};

        _.forOwn(obj, function(v, k) {
            if(_.isPlainObject(v))
                v = _.deepMapKeys(v, fn);
            x[fn(v, k)] = v;
        });

        return x;
    }
});

and here's a more abstract mixin, that recursively applies any given mapper:

_.mixin({
    deep: function (obj, mapper) {
        return mapper(_.mapValues(obj, function (v) {
            return _.isPlainObject(v) ? _.deep(v, mapper) : v;
        }));
    },
});

Usage (returns the same as above):

obj = _.deep(obj, function(x) {
    return _.mapKeys(x, function (val, key) {
        return key + '_hi';
    });
});

Another option, with more elegant syntax:

_.mixin({
    deeply: function (map) {
        return function(obj, fn) {
            return map(_.mapValues(obj, function (v) {
                return _.isPlainObject(v) ? _.deeply(map)(v, fn) : v;
            }), fn);
        }
    },
});


obj = _.deeply(_.mapKeys)(obj, function (val, key) {
    return key + '_hi';
});