PureBasic

Call a JavaScript Function Returning a Boolean

See more JavaScript Examples

Demonstrates how to call a JavaScript function that returns a boolean. PureBasic

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

Procedure ChilkatExample()

    success.i = 0

    ; This is the JavaScript function we'll call:

    ; function isEven(number) {
    ;     return number % 2 === 0;
    ; }

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

    CkStringBuilder::ckAppend(sbScript,"function isEven(number) { return number % 2 === 0; }")

    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

    CkJsonObject::setCkEmitCompact(result, 0)

    ; Call Eval to add the function to the context's global object
    success = CkJs::ckEval(js,sbScript,result)
    If success = 0
        ; Examine the result for an exception.
        Debug CkJsonObject::ckEmit(result)

        ; Also examine the LastErrorText.
        Debug CkJs::ckLastErrorText(js)
        CkStringBuilder::ckDispose(sbScript)
        CkJs::ckDispose(js)
        CkJsonObject::ckDispose(result)
        ProcedureReturn
    EndIf

    ; ------------------------------------------------------------------------------
    ; Call the function isEven(8)

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

    ; Create JSON specifying the function name and arguments

    ; {
    ;   "name": "isEven",
    ;   "args": [ 8 ]
    ; }

    CkJsonObject::ckUpdateString(funcCall,"name","isEven")
    CkJsonObject::ckUpdateInt(funcCall,"args[0]",8)

    success = CkJs::ckCallFunction(js,funcCall,result)
    If success = 0
        ; Examine the result for an exception.
        Debug CkJsonObject::ckEmit(result)

        ; Also examine the LastErrorText.
        Debug CkJs::ckLastErrorText(js)
        CkStringBuilder::ckDispose(sbScript)
        CkJs::ckDispose(js)
        CkJsonObject::ckDispose(result)
        CkJsonObject::ckDispose(funcCall)
        ProcedureReturn
    EndIf

    Debug CkJsonObject::ckEmit(result)

    ; Output:
    ; {
    ;   "type": "bool",
    ;   "value": true
    ; }

    retval.i = CkJsonObject::ckBoolOf(result,"value")
    Debug Str(retval)

    ; Output:
    ; 1


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


    ProcedureReturn
EndProcedure