Question

18

Iterate over object attributes and modify them

rated 0 times [ 24] [ 6] / answers: 1 / hits: 71296 / 10 Years ago, wed, september 24, 2014, 12:00:00

Underscore.js provides _.each and _.map on collections, which is nice, but I need to iterate over all attributes of my object. I need to modify the values and preserve the keys. E.g. I've got something like: {a:1, b:2, c:3} and I need to perform an operation that changes the value but keeps the keys. Let's say, I'll calculate squares, I should get {a:1, b:4, c:9}. The question is: how to do that using underscore (not interested in vanilla javascript)? I'd love a method like:

var a = {a:1, b:2, c:3}

_.magic(a, function(item){ return item*item; });

Additionally, it would be great if this was possible to chain it, since I'm doing a map, dump result to perform each and then use a map again (because I need to).

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emanir

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3 Years ago

answered 10 Years ago zahrafrancisr · Accepted Answer

I looked a little bit more into some of my snippets to see if there was an option to mutate the original object, but I didn't find anything interesting, so I'd go with this :

var original = {a:1, b:2, c:3};

var squaredValues = _.object(_.map(original, function (value, key) {

    return [key, value * value];

}));

I'm hoping there's a more elegant solution though.