This idiom or expression means:

Quickly.
Very fast.

He is the fastest locksmith I’ve ever seen. He unlocked the door before I could say “This is the door!”

This idiom or expression means:

Quickly.
Very fast.
At any time.

Don’t worry! Just call me and I’ll be there at a moment’s notice.

This idiom or expression means:

Quickly.
Very fast.

My wife is very strong. She could break my neck just like that!

Nother example:
A. Did it take them long to change your tire?
B. No, they did it just like that!!

This idiom or expression means:

Acting too quickly or without thinking.
Starting something before you’re supposed to.

Q. Detective, the man you’re holding has only one ear. Is it true he’s the One Eared Burglar?
A. Sorry, we won’t jump the gun on his identity before a full investigation!

This idiom or expression means:

Quickly.
Very fast.

In this dry weather you can lose your house to fire in the blink of an eye.

This is an abbreviation for:

As Soon As Possible.

I need your help ASAP.

This idiom or expression like sentence means:

Do it quickly.
Come back soon.
Don’t take too much time.

This idiom or expression means:

Fast.
Quickly.

Before the recession everybody was making money hand over fist.

This idiom or expression means:

Quickly.
Right away.

When someone says “Come here, on the double,” they mean something like “Come here, right now.”