Ruby Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a String

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

require 'chilkat'

success = false

#  This is the JavaScript function we'll call:

#  function greet(name) {
#      return "Hello, " + name + "!";
#  }

sbScript = Chilkat::CkStringBuilder.new()
sbScript.Append("function greet(name) { return \"Hello, \" + name + \"!\"; }")

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 greet("Michael")

funcCall = Chilkat::CkJsonObject.new()

#  Create JSON specifying the function name and arguments

#  {
#    "name": "greet",
#    "args": [ "Michael" ]
#  }

funcCall.UpdateString("name","greet")
funcCall.UpdateString("args[0]","Michael")

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": "string",
#    "value": "Hello, Michael!"
#  }

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

#  Output:
#  Hello, Michael!