When your data contains discrete, non-numeric property values that you need to format or convert before displaying, d3.scaleOrdinal() is the API you need. Maybe you need to convert a “pass”/”fail” field to “green”/”red” for coloring your bubble chart? This lesson shows you exactly what to do.

function scaleOrdinal(){    var ordinalScale = d3.scaleOrdinal()        .domain([‘poor‘, ‘good‘, ‘great‘])        .range([‘red‘, ‘white‘, ‘green‘]);    console.log(ordinalScale(‘good‘));    console.log(ordinalScale(‘great‘));    console.log(ordinalScale(‘poor‘));}

[D3] Create Labels from Non-numeric Data with Ordinal Scales in D3 v4