SQL Server

Call a JavaScript Function Returning an Integer

See more JavaScript Examples

Demonstrates how to call a JavaScript function that returns an integer. SQL Server

-- 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

    -- ----------------------------------------------------------------------------------
    -- The Javascript function called in this example is shown at the bottom of this page.
    -- -----------------------------------------------------------------------------------

    -- In this example, we'll load the Javascript function definition from a file.
    -- It doesn't need to come from a file.  It could just as easily be loaded from a string.
    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, 'LoadFile', @success OUT, 'js_call_function.js', 'utf-8'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @sbScript, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sbScript
        RETURN
      END

    -- Note: Each instance of a Chilkat Js object automatically establishes
    -- its own internal runtime and context.  Applications do not need to explicitly create
    -- the JavaScript runtime or context.
    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 (shown at the bottom of this page) 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

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

    -- The expected output is "undefined":

    -- {
    --   "type": "undefined",
    --   "value": "undefined"
    -- }

    --    When Eval processes a script containing only a function declaration,
    --    it successfully performs the action (the function becomes defined).
    --    However, since the script consists of a statement that produces no value,
    --    the script's overall completion value is empty. In JavaScript, the
    --    absence of a value is represented by `undefined`.
    -- 
    --    Therefore, the Eval call returns `undefined`.

    -- ------------------------------------------------------------------------------
    -- Call the function calculateScore("Player1", 10, 20)

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

    -- Create JSON defining the function call:

    -- {
    --   "name": "calculateScore",
    --   "args": [ "Player1", 10, 20 ]
    -- }

    EXEC sp_OAMethod @funcCall, 'UpdateString', @success OUT, 'name', 'calculateScore'
    EXEC sp_OAMethod @funcCall, 'UpdateString', @success OUT, 'args[0]', 'Player1'
    EXEC sp_OAMethod @funcCall, 'UpdateInt', @success OUT, 'args[1]', 10
    EXEC sp_OAMethod @funcCall, 'UpdateInt', @success OUT, 'args[2]', 20

    EXEC sp_OASetProperty @funcCall, 'EmitCompact', 0
    EXEC sp_OAMethod @funcCall, 'Emit', @sTmp0 OUT
    PRINT @sTmp0

    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": "int",
    --   "value": 37
    -- }

    DECLARE @retval int
    EXEC sp_OAMethod @result, 'IntOf', @retval OUT, 'value'

    PRINT 'retval = ' + @retval

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


END
GO