registerCustomXPathFunction

Type: Function

How to get registerCustomXPathFunction?

JavaScript

import registerCustomXPathFunction from 'fontoxml-selectors/src/registerCustomXPathFunction.js'

Add a custom function for use in XPath expressions and XQuery scripts. This function needs to be annotated using types from the XPath/XQuery Data Model (XDM).

Note: All item types except function() and its subtypes map() and array(*) are currently supported. Refer to the diagram under 1.6.1 Item types to learn more.

Please refer to Extensibility for more details on writing custom XPath functions.

Other

registerCustomXPathFunction(
  {
    namespaceURI: 'http://www.my-app-namespace',
    localName: 'test'
  },
  ['xs:boolean', 'xs:number*'],
  'xs:string?',
  function (dynamicContext, aSingleBoolean, anArrayOfNumbers) {
    // We should return a string, or null
    return aSingleBoolean ? anArrayOfNumbers.length + '' ? null;
  });

Arguments

  1. name

    (Required)

    Type: Object | String

    The name of this test. This can have one of two forms: a tuple of a namespaceURI and a localname, or a prefixed name. The prefix of a name will be resolved using the namespace manager. If this can not be found, a console warning will appear.

  2. signature

    (Required)

    Type: Array<String>

    The signature of the test, as array of strings (e.g. ['item()', 'node()?', 'xs:numeric'])

  3. returnType

    (Required)

    Type: String

    The return type of the test, as sequence type (e.g. 'xs:boolean')

  4. callback

    (Required)

    Type: Function

    The function itself, which gets the dynamicContext and arguments passed

    Arguments

    Returns

Returns

Type: void