zoomable treemap | es2015 d3v3

this iteration converts the code to ES2015 in something like the airbnb style

still d3 version 3

for linting and lebab convenience, the javascript is abstracted out into a new file, drawTreemap.js

would really like to see block converted to d3 version 4

read the Hierarchies section of CHANGES.md, but haven't quite figured out exactly how to use the v4 treemap layout with the custom layout functions in this block 😅🤔

do tweet @micahstubbs if you figure it out 😀

a fork of Zoomable Treemap Template from ganeshv

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Zoomable Treemap

Treemaps for visualizing hierarchical data. Click to zoom to the next level. Click on the top orange band to zoom out. Based on Mike Bostock's Zoomable Treemaps

This template follows pigshell's convention for "gist templates":

• It is supplied data using postMessage(), as a single object of the form { opts: {...}, data: [...] }
• It posts a message to the parent with an object of the form { height: <number> } to enable the framing context to adjust the height of the iframe.
• If the URL does not contain a hash fragment, it displays sample data from the containing gist.

The following options are supported:

{
    title: "", // Title 
    rootname: "TOP", // Name of top-level entity in case data is an array
    format: ",d", // Format as per d3.format (https://github.com/mbostock/d3/wiki/Formatting)
    field: "data", // Object field to treat as data [default: data]
    width: 960, // Width of SVG
    height: 500, // Height of SVG
    margin: { top: 48, right: 0, bottom: 0, left: 0 } // Margin as per D3 convention
}

data is a tree-like object, or an array of tree-like objects. Each non-leaf node of the tree must contain a "key" property and an array of "values". Leaf nodes must contain a "key" and a "value" property.

[
  {
    "key": "Asia",
    "values": [
    {
      "key": "India",
      "value": 1236670000
    },
    {
      "key": "China",
      "value": 1361170000
    },
    ...
  },
  {
    "key": "Africa",
    "values": [
    {
      "key": "Nigeria",
      "value": 173615000
    },
    {
      "key": "Egypt",
      "value": 83661000
    },
    ...
  },
]

Sample data is world population from countries.git.

Data may be easily converted to tree form using d3.nest(). See the first example below.

Examples (to be run in pigshell):

load http://d3js.org/d3.v3.min.js
cat /usr/share/misc/countries.json | to text | jf 'JSON.parse(x)'| rename -f "name,population" -t "key,value" | jf -g 'd3.nest().key(function(d) {return d.region;}).key(function(d) { return d.subregion; }).entries(x)' | iframe -o title="World Population",rootname="World" -g '/ganeshv/raw/6a8e9ada3ab7f2d88022/#wait'