Underscore equivalent of _.pick for arrays

Question

I understand that pick is used to get back an object with only specified properties:

_.pick({name: \'moe\', age: 50, userid: \'moe1\'}, \'name\', \'age\');
=>         


        

Answer 1

You have to use _.map and apply the same _.pick on all the objects.

var data = [{name: 'moe1', age: 30, userid: 'moe1'},
            {name: 'moe2', age: 50, userid: 'moe1'},
            {name: 'moe3', age: 60, userid: 'moe1'}];

var result = _.map(data, function(currentObject) {
    return _.pick(currentObject, "name", "age");
});

console.log(result);

Output

[ { name: 'moe1', age: 50 },
  { name: 'moe2', age: 50 },
  { name: 'moe3', age: 50 } ]

If you want to get the objects in which the age is > 50, you might want to do, like this

var data = [{name: 'moe1', age: 30, userid: 'moe1'},
            {name: 'moe2', age: 50, userid: 'moe1'},
            {name: 'moe3', age: 60, userid: 'moe1'}];

function filterByAge(currentObject) {
    return currentObject.age && currentObject.age > 50;
}

function omitUserId(currentObject) {
    return _.omit(currentObject, "userid");
}

var result = _.map(_.filter(data, filterByAge), omitUserId);    
console.log(result);

Output

[ { name: 'moe3', age: 60 } ]

You can do the same with chaining, as suggested by rightfold, like this

var result = _.chain(data).filter(filterByAge).map(omitUserId).value();