DocumentsSearch.reduce
DocumentsSearch.reduce( reducer as function, seed as anyValue ) as DocumentsSearch
Summary
Specifies a function similar to Array.prototype.reduce() to apply to each document within the slice. See the Usage Notes for details.
| Parameters | |
|---|---|
| reducer | The reducing function. |
| seed | The initial reduced value passed to the reducing function. |
Usage Notes
The reducer function is called once for each matched document. The value returned by the last call becomes the final reduced result. The reducer function should have the following signature:
function (prev, current, index, state)
Where the parameters contain the following:
prev- The output returned by the previous call, or the seed value on the first call.
current- The current document.
index- The number of the current document.
state- A state object with a boolean-valued
isLast> property that indicated the last call. You can set it to true to prematurely halt the reduction.
You cannot use this method in conjunction with
DocumentsSearch.map.
See Also
- Transforming Results with Map and Reduce in the Search Developer's Guide
Example
// Use a custom reducer, with an initial seed value
const jsearch = require('/MarkLogic/jsearch.sjs');
jsearch.documents()
.where(cts.jsonPropertyValueQuery('author','Mark Twain'))
.reduce(function (prev, match, index, state) {
// do something
}, {count: 0, value: 0, matches: []})
.result()