JS - deep map function

Question

Underscore.js has a very useful map function.

_.map([1, 2, 3], function(num){ return num * 3; });
=> [3, 6, 9]
_.map({one: 1, two: 2, three: 3         


        

Answer 1

Based on @megawac response, I made some improvements.

function mapExploreDeep(object, iterateeReplace, iterateeExplore = () => true) {
    return _.transform(object, (acc, value, key) => {
        const replaced = iterateeReplace(value, key, object);
        const explore = iterateeExplore(value, key, object);
        if (explore !== false && replaced !== null && typeof replaced === 'object') {
            acc[key] = mapExploreDeep(replaced, iterateeReplace, iterateeExplore);
        } else {
            acc[key] = replaced;
        }
        return acc;
    });
}

_.mixin({
    mapExploreDeep: mapExploreDeep;
});

This version allows you to replace even objects & array themselves, and specify if you want to explore each objects/arrays encountered using the iterateeExplore parameter.

See this fiddle for a demo