What's the Difference Between Tilde (~) and Caret (^) in a `package.json` file?

Naveera A.

The Problem

Dependencies in a package.json file often contain a tilde (~) or caret (^) sign before the version number. What do these signs mean, and what is the difference between them?

The Solution

All npm packages must adhere to the Semantic Versioning specification.

So if a package version looks like this 2.1.4, each of these numbers has a meaning.

2.1.4

This number refers to a patch release, which means it is a bug fix and is backward compatible.

2.1.4

This number refers to a minor release, which means new features have been added but it is still backward compatible.

2.1.4

This number refers to a major release, which means that it introduces major changes and may break backward compatibility.

We can specify which releases to accept while updating a package by using special signs in front of the version number in our package.json file.

Using a Tilde (~)

Using a tilde sign before our version number means that we can accept only a patch release when updating our package.

Using a Caret (^)

Using a caret (^) sign means that we can accept minor releases and patch releases, but not a major release when updating our package.

Using an Asterisk (*)

Using an asterisk means “accept all releases”, but this is not advisable as it will accept major releases and may break our code.

Example

Let’s say we are using the lodash package in a project. We currently have version 3.8.0 installed. Lodash announces a new release with version number 3.9.0.

Our package.json file looks like the following:

"dependencies": {
    "lodash": "~3.8.0"
},

When we update our packages, the lodash package will not update because we have specified not to accept a minor release using ~.

In order to accept this release we will need to change the ~ to ^ like so:

"dependencies": {
    "lodash": "^3.8.0"
},

The npm server calculator is a fun tool to master versioning numbers and ranges.

Further Reading

• About semantic versioning
• semver’s Tilde Ranges
• package.json dependencies
• semver documentation