如何在JavaScript中判断一个字符串是否包含某个字符？
user
```json
{
  "method": "includes",
  "description": "The `includes` method checks if a string contains a specified character or substring.",
  "syntax": "string.includes(searchValue, position)",
  "parameters": {
    "searchValue": "The character or substring to search for.",
    "position": "(Optional) The position in the string to start the search from."
  },
  "returnValue": "Returns true if the string contains the specified character or substring; otherwise, false."
}
```
assistant