return empty string if condition isn't met

please i want to make the request filter option for location or/and sensorType return an empty string if any of them is null, i’m using select dropdown to change the values of filter.location and filter.sensorType

expected output:

1. if filter.location is null but filter.sensorType is not null then request = …farms?sensortype=abc&page=3
2. if filter.location is not null but filter.sensorType is null then request = …farms?location=abc&page=3
3. if both are null then requests = …farms?page=3

the result i got with my code was:
…farms?location=abc&undefined&page=3

const [filter, setFilter] = useState({
  sensorType: null,
  location: null,
});


// API REQUEST
const {
  data
} = await axios.get(
  `http://localhost:8080/api/farms?${
          filter.location && `location=${filter.location}`
        }${filter.sensorType && `&sensorType=${filter.sensorType}`}&page=${page}`
);

>Solution :

Just use the ternary conditional operator:

condition ? resultIfTruthy : resultIfFalsy

const [filter, setFilter] = useState({
  sensorType: null,
  location: null,
});


// API REQUEST
const {
  data
} = await axios.get(
  `http://localhost:8080/api/farms?${
          filter.location ? `location=${filter.location}` : ''
        }${filter.sensorType ? `&sensorType=${filter.sensorType : ''}`}&page=${page}`
);