Prob with Graduated panel tick mark labels

The code below is a class for rendering a horizontal ruler with ticks each 12 inches and a feet label number every four feet. the problem is that the feet number label shows inches and not feet. hw can I fix it, it is so close to perfect?

//horizontalRuler.js
import * as go from 'gojs';
const $ = go.GraphObject.make
const horizontalRuler = {
    hrulerTemplate: function (sizeMultiplier, width) {
        return $(
            go.Part,
            'Graduated',
            {
                name: 'hruler',
                graduatedMin: 0,
                graduatedMax: width,
                graduatedTickBase: 0,
                graduatedTickUnit: 1,
                //graduatedScale: 1 / 12, // Scale to convert inches to feet
                background: 'transparent',
            },
            new go.Binding('location', '', function (data) {
                var x = 0;
                var y = data.Height * -1 + -20;
                return new go.Point(x * sizeMultiplier, y * sizeMultiplier);
            }),
            $(go.Shape, {
                geometryString: 'M0 0 H' + width * sizeMultiplier
            }),
            $(go.Shape, { geometryString: 'M0 0 v3' }),
            // a longer tick mark every 12 ticks (12 inches)
            $(go.Shape, { geometryString: 'M0 0 v8', interval: 12 }),
            // text label every 48 ticks (4 feet), with a vertical offset
            $(go.TextBlock, {
                segmentOffset: new go.Point(NaN, 12),
                interval: 48, // 4 feet interval
                font: 'bold 6pt sans-serif',
                alignmentFocus: go.Spot.Bottom
            },
                new go.Binding("text", "", function (part) {
                    let feet = Math.floor(part.graduatedValue / 12);
                    return feet.toString() + " ft";
                }).ofObject()
            )
        );
    }
};

export default horizontalRuler;

Instead of a Binding, I think you want to use the TextBlock.graduatedFunction property: TextBlock | GoJS API