dthree dthree - 5 months ago 53
JSON Question

JS - deep map function

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}, function(num, key){ return num * 3; });
=> [3, 6, 9]


I am looking for a similar function that can iterate through nested objects, or deep mapping. After a ton of searching I can't really find this. What I can find is something to pluck a deep object, but not iterate through every value of a deep object.

Something like this:

deepMap({
one: 1,
two: [
{ foo: 'bar' },
{ foos: ['b', 'a', 'r', 's'] },
],
three: [1, 2, 3]
}, function(val, key) {
return (String(val).indexOf('b') > -1) ? 'bobcat' : val;
})


How would one do this?

Sample Output



{
one: 1,
two: [
{ foo: 'bobcat' },
{ foos: ['bobcat', 'a', 'r', 's'] },
],
three: [1, 2, 3]
}

Answer

Here's a Lodash solution using transform

function deepMap(obj, iterator, context) {
    return _.transform(obj, function(result, val, key) {
        result[key] = _.isObject(val) /*&& !_.isDate(val)*/ ?
                            deepMap(val, iterator, context) :
                            iterator.call(context, val, key, obj);
    });
}

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