JavaScript includes()

includes()

includes() 메서드는 문자열 포함 여부를 검색하여, 불린(true, false)을 반환합니다.

"문자열".includes(검색값)
"문자열".includes(검색값, 시작값)

const str1 = "javascript reference";

const currentStr1 = str1.includes("javascript");    //true
const currentStr2 = str1.includes("j");             //true
const currentStr3 = str1.includes("b");             //false
const currentStr4 = str1.includes("reference");     //true
const currentStr5 = str1.includes("reference", 1);  //true
const currentStr6 = str1.includes("reference", 11); //true
const currentStr7 = str1.includes("reference", 12); //false