Hi! I commented about this in your other question. If you are using a kinematicbody2d and move it with
move_and_slide, just passing a constant vector to that function will keep it moving until something block its way. Would you share what code you have already implemented? For example, if you want to keep moving to right, you can just do something like:
var velocity = Vector2(100,0) # Can be any vector2
velocity = move_and_slide(velocity, Vector2.UP)
that will keep moving to right untill it hits something. If it can slide trhough it (like a slope for example) it will adjust the movement.
Is that what you are looking for?
EDIT: Seeing your comment in your other question, i think the problem is that you are reseting velocity to zero when not pressing any action, is that right? That would stop movement.. if you want to keep moving, you should not reset velocity.
And instead of adding
velocity.x += 1 for example, when a key is pressed you could just replace the current value
velocity.x = 1 so if it was moving in some direction and you press another key, it will start moving the other way.