| Parameter | Meaning |
|---|---|
| Collection | An iterable group of elements. This can be an array or an object. |
| Function | A function that takes 1 input, and returns one output. |
| BiFunction | A function that takes 2 inputs, and returns one output. |
| Predicate | A function that takes 1 input, and returns a boolean value. |
| seed | The initial value for a reduction operation. When this is left out, the first element of the collection is used instead. |