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JavaScript Building a MEAN Application Introduction to the MEAN Stack Setting Up an Express Application

Jason Martin
PLUS
Jason Martin
Courses Plus Student 9,316 Points
Posted by Jason Martin
Jason Martin
Courses Plus Student 9,316 Points

npm install express --save-exact

after install I typed "ls node_modules" and I see about 40 items with express being one of them...I noticed you only came out with express.

What did I do wrong here?? I typed npm install express --save-exact

Ken Howard
Ken Howard
Treehouse Guest Teacher
Ken Howard
Ken Howard
Treehouse Guest Teacher

There's a note in the teacher's notes that talks about an error in the videos regarding --save-exact. This flag is only useful when used in conjunction with the --save or --save-dev flag. For instance, you should install Express like this:

npm install express --save --save-exact

Doing this will add the dependency to your project's package.json file and ensure the version number is static (does not begin with ^ or ~ and does not include an x or *). You can learn more about the nuances of npm's versioning system here: https://github.com/npm/node-semver#advanced-range-syntax

3 Answers

Matt F.
Matt F.
9,518 Points
Matt F.
Matt F.
9,518 Points

Hello Jason,

You are not doing anything wrong - those other modules are Express's dependencies. Much like your app will have Express as a dependency - Express itself depends on other libraries/modules.

If you go here, scroll down and you will see on the right side that Express has 25 dependencies - some of which might have their own dependencies.

https://www.npmjs.com/package/express

Jason Martin
Jason Martin
Courses Plus Student 9,316 Points
Jason Martin
Jason Martin
Courses Plus Student 9,316 Points

Great thanks, just got confused because the video only displayed express when the instructor typed out ls node_modules.

Israel Mabhoo
Israel Mabhoo
16,356 Points
Israel Mabhoo
Israel Mabhoo
16,356 Points

npm install express@4.15.2 --save