This command toggles instant construction on and off for both your nation and AI nations. With instant construction on, construction completes within one day (almost instantly).
The syntax for the instantconstruction command is as follows:
Find below working examples of the instantconstruction command.
If instant construction is turned off (default), the above command would enable instant construction for all countries (including AI) in the game. If you have already turned instant construction on, typing the above command into the console again would turn it off. With instant construction on, buildings finish in one day, bypassing their usual build time.