baseline-browser-mapping

By the W3C WebDX Community Group and contributors.

baseline-browser-mapping exposes arrays of browsers compatible with Baseline Widely Available and specified Baseline year feature sets. You can use baseline-browser-mapping to help you determine minimum browser version support for your chosen Baseline feature set.

Limitations

The browser versions in this module come from two different sources:

• MDN's browser-compat-data module.
• Parsed user agent strings provided by useragents.io

MDN browser-compat-data is an authoritative source of information for the browsers it contains. The release dates for the Baseline core browser set and the mapping of downstream browsers to Chromium versions should be considered accurate.

Note At present, the selection criteria for core browser versions compatible with a given feature set is: the final version of each browser prior to the cut off date for that feature set. In the case of Widely Available, this is 30 months in the past and in the case of Baseline years, this is the end of the year specified. In future, when the web-features repository is data complete, it should be possible to determine if earlier browser versions support the specified feature set.

Browser mappings from useragents.io are provided on a best effort basis. They assume that browser vendors are accurately stating the Chromium version they have implemented. The initial set of version mappings was derived from a bulk export in November 2024. This version was iterated over with a Regex match looking for a major Chrome version and a corresponding version of the browser in question, e.g.:

Mozilla/5.0 (Linux; U; Android 10; en-US; STK-L21 Build/HUAWEISTK-L21) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/100.0.4896.58 UCBrowser/13.8.2.1324 Mobile Safari/537.36

Shows UC Browse Mobile 13.8 implementing Chromium 100, and:

Mozilla/5.0 (Linux; arm_64; Android 11; Redmi Note 8 Pro) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.6613.123 YaBrowser/24.10.2.123.00 SA/3 Mobile Safari/537.36

Shows Yandex Browser Mobile 24.10 implementing Chromium 128. The Chromium version from this string is mapped to the main Chrome version from MDN browser-compat-data.

Note Where possible, approximate release dates have been included based on useragents.io "first seen" data. However, useragents.io does not have "first seen" dates prior to June 2020. However, these browsers' Baseline compatibility is determined by their Chromium version, so their release dates are more informative than critical.

This data is updated on a daily basis using a script triggered by a GitHub action. Useragents.io provides a private API for this module which exposes the last 7 days of newly seen user agents for the currently tracked browsers. If a new major version of one of the tracked browsers is encountered with a Chromium version that meets or exceeds the previous latest version of that browser, it is added to the src/data/downstream-browsers.json file with the date it was first seen by useragents.io as its release date.

Prerequisites

To use this package, you'll need:

• Node.js (a supported current, active LTS, or maintenance LTS release)

Install

To install the package, run:

npm install --save baseline-browser-mapping

If you wish to specify which version of @mdn/browser-compat-data (or manage its upgrades explicitly, such as with Dependabot), then install the latest @mdn/browser-compat-data too. Run:

npm install --save @mdn/browser-compat-data@latest

Updating this module and @mdn/browser-compat-data regularly is recommended to ensure you have the most up to date downstream browsers.

Usage

Get Baseline Widely Available browser versions

To get the current list of minimum browser versions compatible with Baseline Widely Available features from the core browser set, call the getMinimumWidelyAvailable method:

import { getMinimumWidelyAvailable } from "baseline-browser-mapping";

getMinimumWidelyAvailable();

Executed on 29th November 2024, the above code returns the final version of each core browser released on or before 24th May 2022 i.e. 30 months before the date of execution:

[
  {
    browser: "chrome",
    version: "102",
    release_date: "2022-05-24",
    engine: null,
    engine_version: null,
  },
  {
    browser: "chrome_android",
    version: "102",
    release_date: "2022-05-24",
    engine: null,
    engine_version: null,
  },
  {
    browser: "edge",
    version: "101",
    release_date: "2022-04-28",
    engine: null,
    engine_version: null,
  },
  {
    browser: "firefox",
    version: "100",
    release_date: "2022-05-03",
    engine: null,
    engine_version: null,
  },
  {
    browser: "firefox_android",
    version: "100",
    release_date: "2022-05-03",
    engine: null,
    engine_version: null,
  },
  {
    browser: "safari",
    version: "15.5",
    release_date: "2022-05-16",
    engine: null,
    engine_version: null,
  },
  {
    browser: "safari_ios",
    version: "15.5",
    release_date: "2022-05-16",
    engine: null,
    engine_version: null,
  },
];

If you need a list of all compatible versions, you can import and call:

import { getMinimumWidelyAvailable } from "baseline-browser-mapping";

getAllWidelyAvailable();

Get Baseline Widely Available compatible browser versions as of a specific date

To get the minimum browser versions that supported Baseline Widely Available on a specific date, call getMinimumWidelyAvailableOnDate or geAllWidelyAvailableOnDate, passing the desired date in the format YYYY-MM-DD:

import { getMinimumWidelyAvailableOnDate } from "baseline-browser-mapping";

getMinimumWidelyAvailableOnDate("2021-03-19");

This would return the final version of each core browser released on or before 19th September 2018 i.e. 30 months before 19th March 2021.

If you need a list of all compatible versions, you can import and call:

import { getAllWidelyAvailableOnDate } from "baseline-browser-mapping";

getAllWidelyAvailableOnDate("2021-03-19");

Get Baseline year compatible browser versions

To get the list of browser versions that support a particular year's Baseline feature set, call getMinimumByYear or getAllByYear passing the desired year in the format YYYY:

import { getMinimumByYear } from "baseline-browser-mapping";

getMinimumByYear("2020");

If you need a list of all compatible versions, you can import and call:

import { getAllByYear } from "baseline-browser-mapping";

getAllByYear("2020");

Including downstreambrowsers

Each of the methods above can take an optional final boolean parameter includeDownstream. The default for this in all functions is false. To include downstream browsers, pass true as the final parameter when you call the function:

getAllWidelyAvailable(true)

getMinimumWidelyAvailableOnDate('2021-03-19' true)

getMinimumByYear('2020', true)

Passing true will include the appropriate versions of the browsers listed as "Core" = false below.

Currently included browsers

Note All the non-core browsers currently included implement Chromium. Their inclusion in any of the above methods is based on the Baseline feature set supported by the Chromium version they implement, not their release date.

Helping out and getting help

baseline-browser-mapping is part of the W3C WebDX Community Group's web-features project. Go to web-platform-dx/web-features for more information on contributing or getting help.