JSFiddle - React, Tailwind, and code Playground
JavaScript
var ar = [ {num:1, str:"a"}, {num:2, str:"b"}, {num:3, str:"c"} ];
var newArray = [];
for (var i = 0, len = ar.length; i<len; i++) {
if (ar[i].str == "a")
{newArray.push(ar[i]);};
};
console.log(newArray);