Perl

Call a JavaScript Function Returning an Integer

See more JavaScript Examples

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

use chilkat();

$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.
$sbScript = chilkat::CkStringBuilder->new();
$success = $sbScript->LoadFile("js_call_function.js","utf-8");
if ($success == 0) {
    print $sbScript->lastErrorText() . "\r\n";
    exit;
}

#  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.
$js = chilkat::CkJs->new();

$result = chilkat::CkJsonObject->new();
$result->put_EmitCompact(0);

#  Call Eval to add the function (shown at the bottom of this page) to the context's global object
$success = $js->Eval($sbScript,$result);
if ($success == 0) {
    #  Examine the result for an exception.
    print $result->emit() . "\r\n";

    #  Also examine the LastErrorText.
    print $js->lastErrorText() . "\r\n";
    exit;
}

print $result->emit() . "\r\n";

#  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)

$funcCall = chilkat::CkJsonObject->new();

#  Create JSON defining the function call:

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

$funcCall->UpdateString("name","calculateScore");
$funcCall->UpdateString("args[0]","Player1");
$funcCall->UpdateInt("args[1]",10);
$funcCall->UpdateInt("args[2]",20);

$funcCall->put_EmitCompact(0);
print $funcCall->emit() . "\r\n";

$success = $js->CallFunction($funcCall,$result);
if ($success == 0) {
    #  Examine the result for an exception.
    print $result->emit() . "\r\n";

    #  Also examine the LastErrorText.
    print $js->lastErrorText() . "\r\n";
    exit;
}

print $result->emit() . "\r\n";

#  Output:

#  {
#    "type": "int",
#    "value": 37
#  }

$retval = $result->IntOf("value");
print "retval = " . $retval . "\r\n";

JavaScript

function calculateScore(name, pointsA, pointsB) {
    // Return length of name + both scores
    return name.length + pointsA + pointsB;
    }