Get part of JS object

Question

Not sure if the title of the question is doing it justice, but here is an example. I have object:

Click to copy

var plumber = {
  name: 'Mario',
  age: 42,
  game: 'Super Mario'
}

I am looking for an elegant way of using either jQuery or Undescore to get key and value from this object.

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// foo() would be desired elegant function
plumber.foo('name')
#> { name: 'Mario' }
// or even better
plumber.foo(['name','age'])
#> { name: 'Mario', age: 16 }

Thank you!

Answer 1

Underscore.js has _.pick that does exactly that:

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var new_obj = _.pick(obj, ['name', 'age']);

Answer 2

I think you could approach this two ways (without either of those two libraries). You can either pass the function an array of keys or you could pass it a variable number of arguments.

fiddle

Using an array

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var plumber = {
  name: 'Mario',
  age: 42,
  game: 'Super Mario'
}

var splitObject = function (obj, keys) {
    var holder = {};
    keys.forEach(function (d) {
        holder[d] = obj[d];
    })
    return holder;
}

var example = splitObject(plumber, ["name", "age"]);

console.log("example #1", example);

Using a variable number of arguments

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var variableArguments = function (obj) {
    var keys = Array.prototype.slice.apply(arguments).slice(1),
        holder = {};
    keys.forEach(function (d){
        holder[d] = obj[d];
    })
    return holder;
}

var example2 = variableArguments(plumber, "name", "age");
console.log("example #2", example2);

Underscore.js probably has its own function for this. You'd have to check the documentation.

edit:

pick is probably the most appropriate function, as per the comments above.