메서드 (padStart / padEnd)

padStart(), padEnd()

주어진 길이에 맞게 앞/뒤 문자열을 채우고, 새로운 문자열을 반환한다.

    const str1 = "123"
    const currentStr1 = str1.padStart(1, "0");                 // 123
    const currentStr2 = str1.padStart(2, "0");                 // 123
    const currentStr3 = str1.padStart(3, "0");                 // 123
    const currentStr4 = str1.padStart(4, "0");                 // 0123     // 길이가 4자리로 늘어나기에 0추가
    const currentStr5 = str1.padStart(5, "0");                 // 00123
    const currentStr6 = str1.padStart(6, "0");                 // 000123
    const currentStr7 = str1.padStart(6, "1");                 // 111123
    const currentStr8 = str1.padStart(6, "12");               // 121123
    const currentStr9 = str1.padStart(6, "123");             // 123123
    const currentStr10 = str1.padStart(6, "1234");         // 123123
    const currentStr11 = str1.padStart(6);                      //    123
    
    const currentStr12 = str1.padEnd(1, "0");             // 123
    const currentStr13 = str1.padEnd(2, "0");             // 123
    const currentStr14 = str1.padEnd(3, "0");             // 123
    const currentStr15 = str1.padEnd(4, "0");             // 1230     // 길이가 4자리로 늘어나기에 0추가
    const currentStr16 = str1.padEnd(5, "0");             // 12300
    const currentStr17 = str1.padEnd(6, "0");             // 123000
    const currentStr18 = str1.padEnd(6, "1");             // 123111
    const currentStr19 = str1.padEnd(6, "12");           // 123121
    const currentStr20 = str1.padEnd(6, "123");         // 123123
    const currentStr21 = str1.padEnd(6, "1234");       // 123123
    const currentStr22 = str1.padEnd(6);                    // 123___   //_은 공백를 의미