console.log("Hello World!"); let src = `1号 2号 11号 12号 111号 123号`; let target = src.replace(/^(?:(\d)|(\d\d)|(\d{3}))(?=号)/gm,'00$1,0$2,$3'); console.log(target, '\n------------------'); target = target.replace(/0*,/gm, ''); console.log(target);