Log Level

const re = new RegExp("\\b(TRACE|DEBUG|INFO|WARN|ERROR|FATAL)\\b", "g");
const input = "[INFO] Server started. [ERROR] Connection failed.";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

import re

pattern = re.compile(r"\b(TRACE|DEBUG|INFO|WARN|ERROR|FATAL)\b")
input_text = "[INFO] Server started. [ERROR] Connection failed."
for m in pattern.finditer(input_text):
    print(m.group(0))

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`\b(TRACE|DEBUG|INFO|WARN|ERROR|FATAL)\b`)
	input := `[INFO] Server started. [ERROR] Connection failed.`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}