A semitransparent print or log function for TypeScript or JavaScript

utils.ts

let fnNameMatcher = /([^(]+)@|at ([^(]+) \(/;

function fnName(str: string) {
  let regexResult = fnNameMatcher.exec(str) as string[];
  if (regexResult) {
    return regexResult[1] || regexResult[2];
  } else { return ''; }
}

export function log(...messages: any[]) {
  let logLines = (new Error().stack as string).split('\n');
  let callerName = fnName(logLines[1]);

  if (callerName !== null) {
    if (callerName !== 'log') {
      console.log(callerName, ...messages);
    } else {                             
      console.log(fnName(logLines[2]), ...messages);
    }
  } else {
    console.log(...messages);
  }
  return messages[0];
}