includes()

문자열 메서드 : 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

includes() 예제

[1, 2, 3].includes(2);     // true
[1, 2, 3].includes(4);     // false
[1, 2, 3].includes(3, 3);  // false
[1, 2, 3].includes(3, -1); // true
[1, 2, NaN].includes(NaN); // true