#!/usr/bin/env python
# coding: utf-8

# Sometimes you need to load some javascript before displaying output.
# 
# RequireJS handles this if your dependencies can be expressed that way (not always possible).
# 
# If you can't use rqeuire, you can set up a simple watcher that will detect when your loading has finished and trigger callbacks when loading is done. Any outputs produced after loading is finished will display immediately.
# 
# The gist is two methods:
# 
# 1. `mything.when_ready` a function that will fire a callback as soon as possible, but not before our resources (whatever they are) are ready.
# 2. `mything.get_ready` a function to call when you are done loading, to signal that everything is ready. When called, any delayed callbacks will fire.
# 

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get_ipython().run_cell_magic('javascript', '', "\nvar mything = window.mything = {};\n\nmything._ready = false;\nmything._callbacks = [];\n\nmything.when_ready = function (cb) {\n    if (mything._ready) {\n        // ready, call immediately\n        cb();\n    } else {\n        console.log('not ready, delaying', cb);\n        mything._callbacks.push(cb);\n    }\n}\n\nmything.get_ready = function () {\n    console.log('getting ready')\n    mything._ready = true;\n    var callbacks = mything._callbacks;\n    mything._callbacks = null;\n    callbacks.map(function (cb) {\n        cb();\n    })\n}\n\n// fake a slow thing by calling get_ready after a while\nsetTimeout(function () {\n    mything.get_ready();\n}, 2000)\n")


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get_ipython().run_cell_magic('javascript', '', "\nmything.when_ready(function () {\n    console.log('1')\n})\n")


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get_ipython().run_cell_magic('javascript', '', "\nmything.when_ready(function () {\n    console.log('2')\n})\n")


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