63 lines
1.9 KiB
Markdown
63 lines
1.9 KiB
Markdown
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# `XPathEvaluator`
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The `xpath.parse()` method returns an `XPathEvaluator`, which contains the following methods.
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Each of these methods takes an optional `options` object, which can contain any of the following properties. See the links for each item for further details:
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- `namespaces` - a [namespace resolver](namespace%20resolvers.md)
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- `variables` - a [variable resolver](variable%20resolvers.md)
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- `functions` - a [function resolver](function%20resolvers.md)
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- `node` - the context node for evaluating the expression
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Example usage:
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```js
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var evaluator = xpath.parse('/characters/character[@greeting = $greeting]');
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var character = evaluator.select1({
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node: myCharacterDoc,
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variables: {
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greeting: "Hello, I'm Harry, Harry Potter."
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}
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});
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```
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## `XPathEvaluator` methods
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`evaluate([options])`
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Evaluates the XPath expression and returns the result. The resulting type is determined based on the type of the expression, using the same criteria as [`xpath.select`](xpath%20methods.md).
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`evaluateNumber([options])`
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Evaluates the XPath expression and returns the result as a number.
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`evaluateString([options])`
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Evaluates the XPath expression and returns the result as a string.
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`evaluateBoolean([options])`
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Evaluates the XPath expression and returns the result as a boolean value.
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`evaluateNodeSet([options])`
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Evaluates the XPath expression and returns the result as an XNodeSet. See the [documentation page](#) for details on this interface.
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This is only valid for expressions that evaluate to a node set.
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`select([options])`
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Evaluates the XPath expression and returns an array of the resulting nodes, in document order.
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This is only valid for expressions that evaluate to a node set.
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`select1([options])`
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Evaluates the XPath expression and the first node in the resulting node set, in document order. Returns `undefined` if the resulting node set is empty.
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This is only valid for expressions that evaluate to a node set.
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