How to check if an array contains a string in TypeScript?

Hi everyone! I'm new to TypeScript (previously wrote in plain JavaScript) and ran into a problem when checking if a string exists in an array. I have an array of strings: ```typescript let fruits: string[] = ['apple', 'banana', 'orange']; ``` And I need to check if it contains, for example, 'banana'. In JavaScript I would just write: ```javascript if (fruits.indexOf('banana') !== -1) { ... } ``` or ```javascript if (fruits.includes('banana')) { ... } ``` But in TypeScript I'm getting strange type errors. When I write: ```typescript if (fruits.includes('banana')) { console.log('Found!'); } ``` It works fine, but when I try to use indexOf, the compiler complains: "Argument of type 'string' is not assignable to parameter of type 'never'". I don't understand what this means at all.