JSFiddle - React, Tailwind, and code Playground

JavaScript

var brackets = {
  "{": "}",
  "(": ")",
  "[": "]"
};

function isOpening(b) {
  return Object.keys(brackets).indexOf(b) !== -1;
}

function isClosing(b) {
  return Object.values(brackets).indexOf(b) !== -1;
}

function matches(b1, b2) {
  return typeof(brackets[b1]) !== "undefined" && brackets[b1] === b2;
}