I dont know what a IHM property is.
What does it mean to "import mango"? Mango is a Java application.
I am having a doubt how to install nodejs on mango.
One does not install NodeJS on Mango. You install NodeJS on an operating system.
Also don't create multiple topics in the forum. Please read here before asking any further questions - https://help.infiniteautomation.com/documentation