Npm Semantic Versioning

Summary: in this tutorial, you will learn about the semantic versioning to specify the version for your package or to install a specified version of an external package.

Introduction to semantic versioning in npm #

To make the JavaScript ecosystem more reliable and secure, you should update the version number in the package.json file that follows the semantic versioning specification:

major.minor.patchCopy

For example:

4.17.1Copy

In this version:

• The major version is 4.
• The minor version is 17.
• The patch is 1.

For a specified version, you should increment:

• The major version when you make changes that are not compatible with the previous version.
• The minor version when you add a backward-compatible feature with the previous version.
• The path version when you make bug fixes that are backward-compatible with the previous version.

If you develop a new package, the starting version should be 1.0.0.

When you make one or more bug fixes that are backward-compatible with the version 1.0.0, you increase the third digit 1.0.1.

When you introduce new backward-compatible features, you increment the middle digit and reset the third digit to zero like 1.1.0

However, when you make changes that are not backward-compatible with the previous version, you increase the first digit and reset the middle and last digits to zero e.g., 2.0.0

npm semantic versioning #

The following explains how to calculate the semantic versioning.

1) Carat (a.k.a hat) symbol ^ #

To include any version that is greater than a particular version in the same major range, you use the carat symbol (^):

^1.10.1Copy

2) Tilde symbol ~ #

To include any version that is greater than a particular version in the same minor range, you use the tilde symbol (~):

~1.5.12Copy

3) Comparison operators #

To specify a range of stable versions, you use one of the comparison operators >, <, =, >=, <= :

>1.5Copy

Or you can use the hyphen (-) to specify a range:

1.0.0 - 1.5.0Copy

Note that there are spaces on both sides of the hyphen.

4) Prerelease versions #

To include a prerelease version e.g., alpha and beta, you use the prerelease tag:

1.0.0-alpha.1Copy

To specify a range of prerelease version, you use the comparison like > with a prerelease tag:

>=1.0.0-alpha.0 <1.0.5Copy

5) Include multiple sets of versions #

To include multiple sets of versions, you use || to combine. For example:

<1.2.0 || > 1.2.3Copy

6) Use the x symbol #

Use the x symbol to specify any version. For example, 1.x matches any versions with the major version 1 like 1.0.0, 1.1.2, 1.10.20, etc.

Install a package with a specific version #

To install a package you use the npm install command:

npm install <package_name>Copy

To install a package of specified version, you use the @ sign:

npm install <package_name>@versionCopy

The following example installs the express package with the version 4.x:

npm install express@4.xCopy

It will install the express package with the highest version of 4.x e.g., 4.17.1

Summary #

• npm uses the semantic versioning specification with the format major.minor.patch.