JSFiddle - React, Tailwind, and code Playground

JavaScript

var colorData = [
    {
        colorName: 'Red',
        colorIsInRainbow:true
    },
    {
        colorName: 'Orange',
        colorIsInRainbow: true
    },
    {
        colorName: 'Magenta',
        colorIsInRainbow: false
    }
];

function ColorDataWrapper(colorData){
   this.colorData = colorData;
}

ColorDataWrapper.prototype.colorStartsWithR = function(){
   return this.colorData.colorName.substring(0,1) == "R";
};

for(var i = 0; i < colorData.length; i++){
   colorData[i] = new ColorDataWrapper(colorData[i]);
}

console.log(colorData[0].colorStartsWithR());
console.log(colorData[1].colorStartsWithR());