isJsonString

Checks if the provided string a valid JSON string

• Returns: boolean - True if the input string is valid JSON, false otherwise.

• Parameters: str {string} - The string to validate as a JSON format.

isJsonString('{"name":"John Doe","age":17}'); //true

isJsonString('"name":"John Doe","age":17}'); //false

isJsonString('["apple","grape","ginger"]'); //true