PureBasic

Eval JavaScript Returning Int

See more JavaScript Examples

Demonstrates getting the completion value of a JavaScript that returns an integer. PureBasic

IncludeFile "CkJs.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkJsonObject.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  This example demonstrates getting the completion value of a script,
    ;  where the last evaluated expression is an integer.

    ;  The Javascript run in this example is shown below.

    ;  Load the JavaScript from a file.
    sbScript.i = CkStringBuilder::ckCreate()
    If sbScript.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkStringBuilder::ckLoadFile(sbScript,"js_eval_return_int.js","utf-8")
    If success = 0
        Debug CkStringBuilder::ckLastErrorText(sbScript)
        CkStringBuilder::ckDispose(sbScript)
        ProcedureReturn
    EndIf

    js.i = CkJs::ckCreate()
    If js.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    result.i = CkJsonObject::ckCreate()
    If result.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Run the JavaScript
    ;  Eval returns the completion value of the script. This is generally the value of the last evaluated expression.
    ;  In this case, the last evaluated expression is an int.
    success = CkJs::ckEval(js,sbScript,result)
    If success = 0
        Debug CkStringBuilder::ckLastErrorText(sbScript)
        CkStringBuilder::ckDispose(sbScript)
        CkJs::ckDispose(js)
        CkJsonObject::ckDispose(result)
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(result, 0)
    Debug CkJsonObject::ckEmit(result)

    ;  Output:

    ;  {
    ;    "type": "int",
    ;    "value": 42
    ;  }


    CkStringBuilder::ckDispose(sbScript)
    CkJs::ckDispose(js)
    CkJsonObject::ckDispose(result)


    ProcedureReturn
EndProcedure

JavaScript

const base = 10;
const multiplier = 4;
const offset = 2;

// The last line is a calculation resulting in an integer
// Returns 42.
(base * multiplier) + offset;