How does the _.invoke method work in Lodash?

Question

Background

From the documentation about the invoke method, I read:

Invokes the method named by methodName on each element in collection, returning an array of the results of each invoked method

Thus, I assumed that the following code would be synonymous, but this is not the case:

_.map(items, function(item) {
    return _.omit(item, 'fieldName');
})

_.invoke(items, _.omit, 'fieldName');

In this case, the invoke method produces an array of strings, while the map method returns an array of items with fieldName removed from each item.

Questions

• How can one use the invoke method to achieve the same result as the map function?
• Why did invoke return the array of strings in this particular situation?

var items = [{id:1, name:'foo'}, 
             {id:2, name:'bar'}, 
             {id:3, name:'baz'}, 
             {id:4, name:'qux'}];

console.log(
    _.invoke(items, _.omit, 'id')
);

console.log(
    _.map(items, function(item) {
        return _.omit(item, 'id');
    })
);

<script src="https://getfirebug.com/firebug-lite-debug.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.3.1/lodash.min.js"></script>

Answer 1

Make sure to note which version of lodash you are using.

v4.11.1 uses _.invokeMap when operating over a collection:

_.invokeMap([1,2,3], function () {
    console.log(this)
})