Solution 1:

// Create a new array based on current state:
let floors = [...this.state.floors];

// Add item to it
floors.push({ value: floorName });

// Set state
this.setState({ floors });

Solution 2:

For now, the best possible and simplest way is

  this.setState(previousState => ({
      floors: [...previousState.floors, {"value": value.floorName}]
  }));

Solution 3:

In hooks form u may use

setState((prevVals) => [...prevVals,newVals])