If you have to encode a reserved character (such as ‘/’ or ‘@’) so that it can be passed in a URI path, you may need to encode it twice:
Example:
const ticker = '@SMC/2018',
encodedTicker = encodeURIComponent(encodeURIComponent(ticker)),
uri = `https://someexample.io/${encodedTicker}/load`;
See also: “When to Encode or Decode” if you like to be confused.