JSFiddle - React, Tailwind, and code Playground
by Gwyn Milcote
JavaScript
var imageList = [
{value: 100},
{value: 200},
{value: 300},
{value: 400},
{value: 500}
];
var index = imageList.map(function (img) { return img.value; }).indexOf(200);
console.log(index);