enviPy-bayer/static/js/ketcher2/node_modules/xpath/docs/xpath methods.md

#xpath methods

This page details the methods exposed on the xpath object.

xpath.select(expression[, node[, single]])

Evaluates an XPath expression and returns the result. The return value is determined based on the result type of the expression (which can always be predicted ahead of time):

• A boolean value if the expression evaluates to a boolean value.
• A number if the expression evaluates to a numeric value.
• A string if the expression evaluates to a string.
• If the expression evaluates to a nodeset:
  • An array of nodes if single is unspecified or falsy
  • A single node (the first node in document order) or undefined if single is truthy

node is optional and if specified, is used as the context node for evaluating the expression. (It is necessary if the expression includes any node tests.)

single is optional and is ignored if the expression evaluates to anything other than a nodeset.

xpath.useNamespaces(mappings)

Produces a function with the signature func(expression, node) that evaluates the provided xpath expression with the XML namespace definitions provided in mapppings.

mappings should be an object with namespace prefixes as its property names and namespace URIs as its property values.

Example usage:

var expr = xpath.useNamespaces({ hp: 'http://www.example.com/harryPotter', bk: 'http://www.example.com/books' });
var result = expr('/bk:books/bk:book[@name = "Harry Potter and the Half-Blood Prince"]/hp:characters', myBooks);

xpath.select1(expression[, node])

Alias for xpath.select(expression, node, true). Selects a single node or value.

xpath.parse(expression)

Creates a parsed expression. See the [documentation page](parsed expressions.md) for details.