How do I access a Bokeh (Python) variable with JS?

Question

I'm making a dropdown which displays a certain plot depending on what is selected.

I've made my dropdown and begun my CustomJS callback function. At the moment, all I want to do is log whatever option is selected in the dropdown, but obviously I cant just console.log(myDropDownMenu.value);

myDropDownMenu = Select(options=['uniform', 'normal', 'lognormal'], value='uniform', title='Distribution')

callback = CustomJS(args=dict(source=source), code=
                    """
console.log("What should go in here?");
""")

myDropDownMenu.js_on_change('value', callback)

So if 'uniform' is selected in the dropdown, I expect 'uniform' to show up in my console... Any ideas?

score 1 · Answer 1 · answered May 09 '19 at 18:56

1

Who would've known it was this easy?

console.log(this.value);

Rubber duck debugging at it's finest.

answered May 09 '19 at 18:56

Ally Alfie

131
11

score 1 · Accepted Answer · answered May 09 '19 at 19:38

By default the callback object cb_obj and callback data cb_data are available in each JS callback. Additionally, when using args callback attribute you can pass arbitrary number of additional objects as long as they are serializable (like source in your example). In your case this is the cb_object so you can access it's value property. You may consider using e.g. Google Chrome developers tools (ALT+CMD+I on Mac) to view and inspect those objects in JS console.

Thanks Tony. It's these little things I need to know that the docs I've seen don't seem to cover. — Ally Alfie, May 10 '19 at 09:45

How do I access a Bokeh (Python) variable with JS?

2 Answers2