I'd no sooner lie to you than strangle a puppy.
I'd no sooner lie to you than strangle a puppy. ( I came across it on the internet.)

What does it mean?
...had no sooner done...than...
Here is no 'done'.
The whole sentence doesn't make any sense to me.

Question

I'd no sooner lie to you than strangle a puppy.
I'd no sooner lie to you than strangle a puppy. ( I came across it on the internet.)

What does it mean?
...had no sooner done...than...
Here is no 'done'. 
The whole sentence doesn't make any sense to me.

Answer

This means I would never strangle a puppy, but i would do that before I would lie to you. It’s a way of emphasizing that you would never do something. By the way the two things could be just about anything. 
I’d no sooner eat eat calves liver than jump off a 10 story building.