Execute JavaScript

Executes JavaScript code in the current frame or window of the selected WebDriver. Data can be transferred between KNIME and the JavaScript code, by specifying a return type for the executed code and/or selecting input columns which provide argument values for the executed code.

Arguments can be accessed within JavaScript code through the arguments array. The following argument and return data types are supported:

In case you need to execute code asynchronously, enable the [asyncCallbackMethod] argument. In this case, the last argument given to the executed code is the callback which signals that the code has finished execution. In case you need to return results from your asynchronous code, provide it as argument to the callback method. For example, the following JavaScript code causes the browser to sleep for five seconds, then the execution continues:

var callback = arguments[arguments.length - 1]; // last argument is callback
window.setTimeout(function() {
  console.log('finished');
  callback(); // invoke the callback to continue execution
}, 5000);

Hint: In case you want to return complex data from your JavaScript code (objects or arrays), you can serialize them as follows and use the return type “String”:

var complexObject = {
  property1: 'foo',
  property2: [ 'bar', 'baz' ],
  property3: 5  
};
return JSON.stringify(complexObject);
        

Afterwards, you can make use of KNIME’s String to JSON node to convert the string into a JSON cell.

Timeouts for asynchronous execution can be configured in the Start WebDriver node in the “Timeouts” tab: Script timeout.