How to calculate the weights in a Sankey chart? - highcharts

Question

I am considering using a Sankey chart but I fail to clearly understand how to calculate the weights.
Let's assume a case where an entity (one) is split into hello and world, at respectively 70% and 30%.
hello is then split into aaa and bbb, also 70/30.
From the documentation I thought that the weights were relative to the output node (code also in JSFiddle and CodePen -- for some reason the same code refuses to run in the SO snippet below):
Highcharts.chart('container', {
series: [{
keys: ['from', 'to', 'weight'],
data: [
['One', 'hello', 70],
['One', 'world', 30],
['hello', 'aaa', 70],
['hello', 'bbb', 30],
],
type: 'sankey',
}]
});
#container {
min-width: 300px;
max-width: 800px;
height: 400px;
margin: 1em auto;
border: 1px solid silver;
}
<script src="https://code.highcharts.com/modules/sankey.js"></script>
<script src="https://code.highcharts.com/highcharts.js"></script>
<div id="container"></div>
This is not the case, however: both world and bbb have the same size, namely 30.
This means that the weights are absolute: in my case I need to take 100 and distribute it accordingly between world (30), aaa (70*0.7 = 49) and bbb (70*0.3 = 21).
If so, where should I put world as it is auto-calculated from the other data? (it is an "intermediate" result)

Answer 1

I finally worked out the numbers. The key is to use absolute numbers, but compute them for every step.
In the example of my question that would be:
one: 100 (fixed)
world: 30 (fixed)
hello: 70 (fixed)
aaa: 49 (calculated 70*0.7 = 49)
bbb: 21 (calculated 70*0.3 = 21)
This leads to the following code.