What is the rationale for putting save-exact into .npmrc?

[vincentrolfs]

What is the rationale for putting save-exact into .npmrc? I want to understand more about why this is done, since it's not at all obvious why this is a good idea.

In former times, the main argument for save-exact was trying to avoid breakage of production builds, but with package.lock/yarn.lock this argument does not seem to apply anymore.

[beerose]

This is a PR that introduced it: #500

Even with yarn.lock/package.lock etc you still may need it as save-exact=true makes sure that no sliding versions (with ~ or ^ ) will not be installed.

Example:

• you have "some-package": "^1.2.3" in your package.json
• you have the same version in a lock file
• then you deleted node_modules and want to install dependencies again
• and in the meantime there's a new minor version of some-package, e.g. 1.8.0
• package manager will install 1.8.0 if you don't have save-exact=true.