JSFiddle - React, Tailwind, and code Playground

JavaScript

function closest(arr, closestTo){
    
    var closest = Math.max.apply(null, arr);
    
    for(var i = 0; i < arr.length; i++){
        if(arr[i] >= closestTo && arr[i] < closest) closest = arr[i];
    }
    
    return closest;
}


alert(closest([300, 500, 700, 1000, 2000, 3000], 1200))