(SQL Server) Call a JavaScript Function Returning a String

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Note: This example requires Chilkat v11.4.0 or greater.

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-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    -- This is the JavaScript function we'll call:

    -- function greet(name) {
    --     return "Hello, " + name + "!";
    -- }

    DECLARE @sbScript int
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbScript OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OAMethod @sbScript, 'Append', @success OUT, 'function greet(name) { return "Hello, " + name + "!"; }'

    DECLARE @js int
    EXEC @hr = sp_OACreate 'Chilkat.Js', @js OUT

    DECLARE @result int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @result OUT

    EXEC sp_OASetProperty @result, 'EmitCompact', 0

    -- Call Eval to add the function to the context's global object
    EXEC sp_OAMethod @js, 'Eval', @success OUT, @sbScript, @result
    IF @success = 0
      BEGIN
        -- Examine the result for an exception.
        EXEC sp_OAMethod @result, 'Emit', @sTmp0 OUT
        PRINT @sTmp0

        -- Also examine the LastErrorText.
        EXEC sp_OAGetProperty @js, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sbScript
        EXEC @hr = sp_OADestroy @js
        EXEC @hr = sp_OADestroy @result
        RETURN
      END

    -- ------------------------------------------------------------------------------
    -- Call the function greet("Michael")

    DECLARE @funcCall int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @funcCall OUT

    -- Create JSON specifying the function name and arguments

    -- {
    --   "name": "greet",
    --   "args": [ "Michael" ]
    -- }

    EXEC sp_OAMethod @funcCall, 'UpdateString', @success OUT, 'name', 'greet'
    EXEC sp_OAMethod @funcCall, 'UpdateString', @success OUT, 'args[0]', 'Michael'

    EXEC sp_OAMethod @js, 'CallFunction', @success OUT, @funcCall, @result
    IF @success = 0
      BEGIN
        -- Examine the result for an exception.
        EXEC sp_OAMethod @result, 'Emit', @sTmp0 OUT
        PRINT @sTmp0

        -- Also examine the LastErrorText.
        EXEC sp_OAGetProperty @js, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sbScript
        EXEC @hr = sp_OADestroy @js
        EXEC @hr = sp_OADestroy @result
        EXEC @hr = sp_OADestroy @funcCall
        RETURN
      END

    EXEC sp_OAMethod @result, 'Emit', @sTmp0 OUT
    PRINT @sTmp0

    -- Output:
    -- {
    --   "type": "string",
    --   "value": "Hello, Michael!"
    -- }

    DECLARE @retval nvarchar(4000)
    EXEC sp_OAMethod @result, 'StringOf', @retval OUT, 'value'

    PRINT @retval

    -- Output:
    -- Hello, Michael!

    EXEC @hr = sp_OADestroy @sbScript
    EXEC @hr = sp_OADestroy @js
    EXEC @hr = sp_OADestroy @result
    EXEC @hr = sp_OADestroy @funcCall


END
GO