d2-ui/node_modules-react-15/enzyme/docs/api/ShallowWrapper/reduce.md

d2-ui

# `.reduce(fn[, initialValue]) => Any`

Applies the provided reducing function to every node in the wrapper to reduce to a single value.
Each node is passed in as a `ShallowWrapper`, and is processed from left to right.


#### Arguments

1. `fn` (`Function`): A reducing function to be run for every node in the collection, with the
following arguments:
  - `value` (`T`): The value returned by the previous invocation of this function
  - `node` (`ShallowWrapper`): A wrapper around the current node being processed
  - `index` (`Number`): The index of the current node being processed

2. `initialValue` (`T` [optional]): If provided, this will be passed in as the first argument to the
first invocation of the reducing function.



#### Returns

`T`: Returns an array of the returned values from the mapping function...



#### Example

```jsx
class Foo extends React.Component {
  render() {
    return (
      <div>
        <Bar amount={2} />
        <Bar amount={4} />
        <Bar amount={8} />
      </div>
    );
  }
}
```

```jsx
const wrapper = shallow(<Foo />);
const total = wrapper.find(Bar).reduce((amount, n) => amount + n.prop('amount'));
expect(total).to.equal(16);
```


#### Related Methods

- [`.reduceRight(fn[, initialValue]) => Any`](reduceRight.md)
- [`.forEach(fn) => ShallowWrapper`](forEach.md)
- [`.map(fn) => Array<Any>`](map.md)