Plotly table conditional formatting in plotly.js

Hello, I am trying to do something like in plotly. js but can’t seem to get the syntax correct. Can someone please show me an example in plotly.js with conditional formatting? I tried to use:

fill: {
color: [
vals.forEach(function(vd) {
if ( vd.value >= -100) {
} else {

but i just get a column with a black fill.