Question

74

rated 0 times [ 80] [ 6] / answers: 1 / hits: 149334 / 11 Years ago, thu, september 26, 2013, 12:00:00

The map function in underscore.js, if called with a javascript object, returns an array of values mapped from the object's values.

_.map({one: 1, two: 2, three: 3}, function(num, key){ return num * 3; });

=> [3, 6, 9]

is there a way to make it preserve the keys? ie, I want a function that returns

{one: 3, two: 6, three: 9}

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3 Years ago

answered 11 Years ago yosefleod · Accepted Answer

With Underscore

Underscore provides a function _.mapObject to map the values and preserve the keys.

_.mapObject({ one: 1, two: 2, three: 3 }, function (v) { return v * 3; });



// => { one: 3, two: 6, three: 9 }

With Lodash

Lodash provides a function _.mapValues to map the values and preserve the keys.

_.mapValues({ one: 1, two: 2, three: 3 }, function (v) { return v * 3; });



// => { one: 3, two: 6, three: 9 }