# use-includes-instead-of-indexOf Use `.includes` instead of `.indexOf` to check if something is in an array or string. ## Examples of incorrect code for this rule ```js let a = foo.indexOf(bar) >= 0; let a = foo.indexOf(bar) == -1; ``` ## Examples of correct code for this rule ```js let a = foo.includes(bar); let a = foo.indexOf(bar) > 0; ```