How to detect the user browser ( Safari, Chrome, IE, Firefox and Opera ) using JavaScript ?

Example:

function checkBrowser() {                        // Get the user-agent string             let userAgentString =                  navigator.userAgent;                        // Detect Chrome             let chromeAgent =                  userAgentString.indexOf("Chrome") > -1;                        // Detect Internet Explorer             let IExplorerAgent =                  userAgentString.indexOf("MSIE") > -1 ||                  userAgentString.indexOf("rv:") > -1;                        // Detect Firefox             let firefoxAgent =                  userAgentString.indexOf("Firefox") > -1;                        // Detect Safari             let safariAgent =                  userAgentString.indexOf("Safari") > -1;                                // Discard Safari since it also matches Chrome             if ((chromeAgent) && (safariAgent))                  safariAgent = false;                        // Detect Opera             let operaAgent =                  userAgentString.indexOf("OP") > -1;                                // Discard Chrome since it also matches Opera                  if ((chromeAgent) && (operaAgent))                  chromeAgent = false;                        document.querySelector(".output-safari").textContent                         = safariAgent;             document.querySelector(".output-chrome").textContent                         = chromeAgent;             document.querySelector(".output-ie").textContent                         = IExplorerAgent;             document.querySelector(".output-opera").textContent                         = operaAgent;             document.querySelector(".output-firefox").textContent                         = firefoxAgent;         }