Ruby Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a Boolean

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

require 'chilkat'

success = false

#  This is the JavaScript function we'll call:

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

sbScript = Chilkat::CkStringBuilder.new()
sbScript.Append("function isEven(number) { return number % 2 === 0; }")

js = Chilkat::CkJs.new()

result = Chilkat::CkJsonObject.new()
result.put_EmitCompact(false)

#  Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result)
if (success == false)
    #  Examine the result for an exception.
    print result.emit() + "\n";

    #  Also examine the LastErrorText.
    print js.lastErrorText() + "\n";
    exit
end

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

funcCall = Chilkat::CkJsonObject.new()

#  Create JSON specifying the function name and arguments

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

funcCall.UpdateString("name","isEven")
funcCall.UpdateInt("args[0]",8)

success = js.CallFunction(funcCall,result)
if (success == false)
    #  Examine the result for an exception.
    print result.emit() + "\n";

    #  Also examine the LastErrorText.
    print js.lastErrorText() + "\n";
    exit
end

print result.emit() + "\n";

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

retval = result.BoolOf("value")
print retval.to_s() + "\n";

#  Output:
#  true