JavaScript padStart() / padEnd()

padStart / padEnd

padStart() 메서드는 주어진 길이에 맞게 앞/뒤 문자열을 채우고, 새로운 문자열을 반환합니다.

"문자열".padStart(길이)
"문자열".padStart(길이, 문자열)

const str1 = "456";
const currentStr1 = str1.padStart(1, "0");          //456
const currentStr2 = str1.padStart(2, "0");          //456
const currentStr3 = str1.padStart(3, "0");          //456
const currentStr4 = str1.padStart(4, "0");          //0456
const currentStr5 = str1.padStart(5, "0");          //00456
const currentStr6 = str1.padStart(6, "0");          //000456
const currentStr7 = str1.padStart(6, "1");          //111456
const currentStr8 = str1.padStart(6, "12");         //121456
const currentStr9 = str1.padStart(6, "123");        //123456
const currentStr10 = str1.padStart(6, "1234");      //123456
const currentStr11 = str1.padStart(6);              //   456

const currentStr12 = str1.padEnd(1, "0");           //456
const currentStr13 = str1.padEnd(2, "0");           //456
const currentStr14 = str1.padEnd(3, "0");           //456
const currentStr15 = str1.padEnd(4, "0");           //4560
const currentStr16 = str1.padEnd(5, "0");           //45600
const currentStr17 = str1.padEnd(6, "0");           //456000
const currentStr18 = str1.padEnd(6, "1");           //456111
const currentStr19 = str1.padEnd(6, "12");          //456121
const currentStr20 = str1.padEnd(6, "123");         //456123
const currentStr21 = str1.padEnd(6, "124");         //456123
const currentStr22 = str1.padEnd(6);                //456___