Suppose a 5th level fighter with Extra Attack, armed with a greatsword and a javelin.
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.
Suppose the following sequence of events:
- The fighter starts their turn already wielding their greatsword.
- The fighter uses their full movement speed to get to melee range of an enemy.
- The fighter uses their attack action to strike an enemy: The enemy is killed on the first strike.
- The nearest remaining enemy is 15 feet away.
So at this point, can the fighter draw their javelin as their free object interaction for the turn, then throw it at the nearby enemy as their extra attack?
I think this is okay: You can move between attacks, and moving feels like it should be a bigger deal mechanics-wise than a free object interaction.
Moving Between Attacks:
If you take an action that includes more than one weapon attack, you can break up your movement even further by moving between those attacks. For example, a fighter who can make two attacks with the Extra Attack feature and who has a speed of 25 feet could move 10 feet, make an attack, move 15 feet, and then attack again.
The dodgy bit might be letting go of the greatsword with the main hand to draw and throw the javelin. But I think Jeremy Crawford coveres that on Twitter:
A two-handed weapon needs two hands to be used, but not necessarily two to be carried.
This related comment for reaction spells sort of applies here too:
Would this cover Reaction Spells
So it sounds like going from holding a weapon with two hands to holding it with one hand is a non-action.
So I think this checks out.
Just setting up a character that I want to focus on two handed weapons. I would like the ability to attack at range in the same round if I can get it.