JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = ["42.00", 33, 12.02, "30", 10];
var out;

if (typeof(Array.prototype.map == 'function')) {
    out = a.map(function(el){ return typeof(el) !== 'number' ? parseFloat(el) : el });
}
else {
    out = [];
    for (var i = 0; i < a.length; ++i) {
        out[i] = typeof(a[i]) !== 'number' ? parseFloat(a[i]) : a[i];   
    }
}

console.log(out);