Add documentation for N1QL managed Javascript UDFs

Add a new type of javascript user defined function :

• CREATE FUNCTION doc page

https://docs.couchbase.com/server/current/n1ql/n1ql-language-reference/createfunction.html

• Javascript UDFs with Couchbase:

https://docs.couchbase.com/server/current/javascript-udfs/javascript-functions-with-couchbase.html

And any other doc pages necessary.

N1QL Managed Javascript Functions

Allows users to create a Javascript function and its corresponding N1QL function in a single statement.

There is a one to one relationship between the Javascript function and the N1QL UDF.

Edit:

• In N1QL managed JS UDFs the library of javascript code is specified inline along with the SQL++ function creation.

• Functions defined in this inline library of javascript code can only be invoked/ referenced within this library.

           And cannot be accessed in other libraries.

• Note that: All the RBAC pre-requisites, constraints on allowed Javascript constructs, SQL++ invocation methods - are the same for both the existing external JS UDFs and the new N1QL managed JS UDFs.

Syntax

create-function-query-managed-javascript ::= 

'CREATE' ( 'OR' 'REPLACE' )? 'FUNCTION' function '(' params? ')'

               ( 'IF' 'NOT' 'EXISTS' )?

               'LANGUAGE' 'JAVASCRIPT' 'AS' javascript-code

Function : function name

Params : function parameters

Javascript-code : A string that contains Javascript code. It must contain a function definition with the SAME name as the corresponding N1QL function.

The javascript-code can contain multiple function definitions. But these functions can only be referenced within this N1QL function and cannot be shared.

Example:

Create N1QL managed JS UDF:

CREATE FUNCTION func1() LANGUAGE JAVASCRIPT AS "function func1(param1) { return param1+100;}”;

Execute the function:

EXECUTE FUNCTION func1(100);

[

  200

]