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Administrating MarkLogic Server

Server-Side JavaScript

In the new version of Server-Side JavaScript, ValueIterator has been replaced by Sequence. The ValueIterator interface used to represent sequences of value in MarkLogic 8 has been replaced by the new Sequence interface. A Sequence is a JavaScript Iterable object. All functions which previously operated on or returned a ValueIterator now use a Sequence instead.

In many cases, this change is transparent to your code. However, code that depends on the following ValueIterator properties and methods must be changed:

  • ValueIterator.next - Use a for..of loop to iterate over a Sequence. Use fn.head if you just want to pick off the first or only value in a Sequence.

  • ValueIterator.count - Use fn.count instead.

  • ValueIterator.clone - No longer needed. You can iterate over the same Sequence multiple times.

To prepare your code for a possible mixed environment, you might use a safe coding pattern similar to this:

var list = xdmp.arrayValues(...);
if (list instanceof Sequence) {
    ... ML9 idiom ...
} else {
    ... ML8 idiom ...
}

See Sequence in the JavaScript Reference Guide and Sequence in the MarkLogic Server-Side JavaScript Function Reference for more information.

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