Package Version Symbols: ^, ~, and No Symbol Explained

JavaScript
3 minutes read

Introduction

When developing software, it is common to use external libraries or modules written by other developers to avoid writing code from scratch. These external libraries or modules are called packages.

If your project uses third-party packages, you must specify the package version. This is important because different versions of the same package may contain different features, bug fixes, and possibly game-changing changes. 

Package versioning use different symbols to indicate version dependencies. The most common symbols are ^ (caret) and ~ (tilde), or no symbol used. In this tutorial, we will explain the options and see the differences between them

Package Version Parts

A version number typically consists of two or three parts separated by periods, such as 1.2.3 or 1.2.3.4. Each part of the version number represents a different level of change to the software.

Major

The major version is the first part of the version number. It represents breaking changes to the software, such as changes to the API or interface changes that may cause compatibility issues with older versions of the software. 

Minor

The minor version is the second part of the version number. This represents a small but significant change to the software such as new features, bug fixes, and other improvements that do not affect backward compatibility. 

Patch

The patch is the third part of the version number. It represents minor software changes, including bug fixes, security patches, and other minor updates that do not affect functionality or compatibility. 

Build Version/Revision Number

The build version or revision number is additional information some software use. This part of the version number represents a specific build or release of the software and is typically only used for internal tracking purposes.

The Caret Symbol (^)

The caret symbol (^) indicates that the package’s updates are allowed as long as they are not major updates that break backward compatibility. 

For example, if you have a package dependency with a version of  ^1.2.3 it will allow updates up to version 2.0.0 (if available) but not 3.0.0, assuming that version 2.0.0 is backward compatible with version 1.2.3.

Suppose your project depends on the lodash package and you want to allow updates until the next major release, but not after that. You can specify the dependency as follows:

"dependencies": {
    "lodash": "^4.17.11"
}

With this dependency specification, you allow updates up to version 5.0.0 (if available) but not 6.0.0, assuming that version 5.0.0 is backward compatible with version 4.17.11.

The Tilde Symbol (~)

The tilde symbol (~) indicates that you want to allow updates to the package as long as they are within the same minor version. For example, if you have a package dependency with a version of ~1.2.3, it means that you allow updates up to version 1.3.0 but not 2.0.0.

Suppose your project depends on the axios package, and you want to allow updates up to the next minor release, but not the one after that. You can specify the dependency as follows:

"dependencies": {
    "axios": "~0.21.1"
}

With this dependency specification, you allow updates up to version 0.22.0 (if available) but not 1.0.0, assuming that version 0.22.0 is backward compatible with version 0.21.1.

No Symbol

When no symbol is used, it usually means an exact version match is required. For example, if you have a package dependency listed as 1.2.3, it means that only version 1.2.3 of the package is allowed.

Suppose your project depends on the react package, and you want to specify an exact version. You can specify the dependency as follows

"dependencies": {
    "react": "16.8.6"
}

With this dependency specification, only version 16.8.6 of the react package is allowed.

Further Reading

Conclusion

In conclusion, understanding the symbols used in package management systems is crucial to avoid issues with your project’s dependencies. To summarize, the caret symbol (^) allows updates up to the next major version, assuming backward compatibility, while the tilde symbol (~) allows updates up to the next minor version, assuming backward, and if there is no symbol it allows the exact version.

Leave a Reply

Your email address will not be published. Required fields are marked *