openrosa-xpath-evaluator
v3.1.0
Published
Wrapper for browsers' XPath evaluator with added support for OpenRosa extensions.
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2,437
Readme
Openrosa XPath Evaluator
Wrapper for browsers' XPath evaluator with added support for OpenRosa extensions.
For more info on extended XPath expressions/bindings supported by XForms/OpenRosa/OpenDataKit (ODK) see:
Installation
yarn
yarn add openrosa-xpath-evaluator
npm
npm install --save openrosa-xpath-evaluator
Use
Initialisation
const orxe = require('openrosa-xpath-evaluator');
const evaluate = orxe();
Querying
var result = evaluate(
'//ul/li/text()', // XPath expression
document, // context node
null, // namespace resolver
XPathResult.ORDERED_NODE_SNAPSHOT_TYPE
);
// loop through results
for (var i = 0; i < result.snapshotLength; i++) {
var node = result.snapshotItem(i);
alert(node.nodeValue);
}
Dependencies
This library has no explicit dependencies, but expects various DOM & XPath-related values to be supplied by the browser (Element
, Node
, XPathResult
etc.).
To use the ODK digest()
function,
you'll need to add node-forge
to
your project.
Development
Useful resources
- https://www.w3.org/TR/1999/REC-xpath-19991116/
- https://getodk.github.io/xforms-spec/
- https://developer.mozilla.org/en-US/docs/Web/API/XPathEvaluator
- https://developer.mozilla.org/en-US/docs/Web/API/Document/evaluate
- https://developer.mozilla.org/en-US/docs/Web/XPath/Introduction_to_using_XPath_in_JavaScript
- https://developer.mozilla.org/en-US/docs/Web/API/XPathResult
- https://developer.mozilla.org/en-US/docs/Web/API/Node
Known limitations
- namespace:: axis is not supported (but it might work in your browser if you're lucky)
- xpath variables (
$var
) are not supported
Not implemented
The following XPath/ODK/OpenRosa functions are not implemented in this library, but may still work depending on your usage.
XPath 1.0 functions
- instance()
- current()
ODK functions
- pulldata()
- jr:choice-name()
- jr:itext()
- indexed-repeat()
TODO
- arrange source code, e.g.
src/core
andsrc/openrosa
Acknowledgement
This library was developed by Medic Mobile for their Enketo-based application. In 2020, it was transferred to the Enketo organization. Many thanks to Medic Mobile for this very valuable contribution to the Enketo and ODK world.
Development of this application was made possible by: