If I set input as Object, if (input[prefCode] !== null) { currentValue = input[prefCode].toString(); } in the lines above, I see a red underli

If I set input as Object, if (input[prefCode] !== null) { currentValue = input[prefCode].toString(); } in the lines above, I see a red underline under input[prefCode] > Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'Object'. No index signature with a parameter of type 'string' was found on type 'Object'.ts(7053)