What is the purpose of using --save-exact

For example, I use --save-exact when I manage projects with webpack. As you know, when you install a package like npm install --save-dev webpack for example, our package.json will add something like:

"devDependencies": {
    "webpack": "^5.1.3",
}

What does it mean?

When you delete your node_modules folder (for example when you put your files on github)and you make a npm install, maybe a version of any package could be updated and if the version is not a major version (X.0.0), Maybe your application stops working because of update. For example from 5.1.3 maybe the package is going to uptade to 5.1.8
So, the --save-exact will generate the next package.json code

"devDependencies": {
    "webpack": "5.1.3",
}

Whitout the ^, the version of the package of webpack in this case will be always the same 5.1.3.

More reference here about semantic version with NPM:

• About semantic versioning

PDT: Sorry for my poor English.

When using save=true, npm install will automatically add the package into package.json without the need of using npm install --save every time you run the command. save-exact=true will make sure that no sliding versions (with ~ or ^ ) will not be installed.

reference for more information click here

or please go through this https://docs.npmjs.com/cli/install