DocumentsSearch.map
DocumentsSearch.map( mapper as objectOrFuncRef ) as DocumentsSearch
Summary
Specifies a function similar to
Array.prototype.map() to apply to each document within the
slice or the configuration for the built-in mapper. Exclusive with
respect to the documentSearch.reduce clause.
| Parameters | |
|---|---|
| mapper | A configuration object for the built-in mapper, or a reference to a custom mapper function. See the Usage Notes for details. |
Usage Notes
You cannot use this function and DocumentsSearch.reduce
in the same search. You should only call
DocumentSearch.withOptions or
DocumentSearch.result on the result of this operation.
You can pass in either a configuration object for the built-in mapper or a function reference to a custom mapper. The built-in mapper configuration object can have the following properties:
snippets- Controls selection of matching text with either a boolean value or a configuration object having the
preferredMatches,maxMatches,perMatchTokens, andqueryproperties. For details, see Including Snippets of Matching Content in Search Results in the Search Developer's Guideextract- Controls selection by XPath with a configuration object having the
selectedproperty (an enumeration ofinclude|include-with-ancestors|exclude|all) and thepathsproperty. For details, see Extracting Portions of Each Matched Document in the Search Developer's Guidenamespaces- Specifies a configuration object with prefix keys and uri values for resolving XPath expressions used in
extract.returnSimilar- A boolean value controlling whether to return documents similar to each result document.
A custom mapper should have the following signature:
function (currentItem)
Where currentItem is a search result descriptor object.
See DocumentsSearch.result for
an example of what this object can look like. If the mapper function
returns a value, the value is added to the results array
or iterator.
See Also
- Including Snippets of Matching Content in Search Results in the Search Developer's Guide
- Extracting Portions of Each Matched Document in the Search Developer's Guide
- Transforming Results with Map and Reduce in the Search Developer's Guide
Example
// Use the built-in mapper to return snippets instead of documents
const jsearch = require('/MarkLogic/jsearch.sjs');
jsearch.documents()
.where(jsearch.byExample({synopsis: {$word: 'california'}}))
.map({snippet: true})
.result()
Example
// Use the built-in mapper to return snippets, preferrably of
// matches in the "synopsis" property. Return at most 5 tokens around
// the match highlight.
const jsearch = require('/MarkLogic/jsearch.sjs');
jsearch.documents()
.where(cts.wordQuery('california'))
.map({snippet: {
preferredMatches: ['synopsis'],
perMatchTokens: 5
}})
.result()
Example
// Use the built-in mapper to extract just the "title" and "author"
// JSON properties from matched documents.
const jsearch = require('/MarkLogic/jsearch.sjs');
jsearch.documents()
.where(jsearch.byExample({synopsis: {$word: 'California'}}))
.map({extract: {paths: ['/title', '/author']}})
.result()
Example
// Use the built-in mapper to return both snippets and documents.
const jsearch = require('/MarkLogic/jsearch.sjs');
jsearch.documents()
.where(jsearch.byExample({synopsis: {$word: 'California'}}))
.map({snippet: true, extract: {selected: 'all'}})
.result()
Example
// Use a custom mapper to insert a new property in output document
// returned for each match.
const jsearch = require('/MarkLogic/jsearch.sjs');
jsearch.documents()
.where(cts.jsonPropertyValueQuery('author','Mark Twain'))
.map(function (value) {value.iWasHere = true; return value;})
.result()
// This example produces output similar to the following, where
// the "iWasHere" property was added to each result by the
// custom mapper. (Some search results were elided for brevity.)
//
// { "results": [
// { "index": 0,
// "uri": "/books/twain4.json",
// "score": 14336,
// "confidence": 0.43245348334312,
// "fitness": 0.7490314245224,
// "document": {
// "title": "Adventures of Huckleberry Finn",
// "author": "Mark Twain",
// "edition": {
// "format": "hardback",
// "price": 18
// },
// "synopsis": "The adventures of Huck, a boy of 13, ..."
// },
// "iWasHere": true
// }, ...
// ],
// "estimate": 4
// }