compute-baseline

By the W3C WebDX Community Group and contributors.

compute-baseline computes Baseline statuses from @mdn/browser-compat-data feature keys. You can use compute-baseline to help you find interoperable web platform features, propose new web-features features, or compare support between features.

compute-baseline also provides utility classes for working with @mdn/browser-compat-data generally.

Limitations

If you need authoritative Baseline statuses, check out the web-features package first. Most of the time, the status information provided by web-features is the best representation of a feature overall.

If you need to know the Baseline status of a specific browser compatibility data entry within a web-features feature, then you can use the getStatus method. The web-features package and the getStatus method are the only ways to get a status that have completed the full Baseline editorial review process.

All other invocations of compute-baseline have not received editorial review. Don't use compute-baseline to generate publishable Baseline statuses for arbitrary web platform features. If you're not sure whether your application fits with the definition of Baseline, please file an issue.

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 compute-baseline

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

Usage

Get a Baseline status for a portion of a feature

To get a Baseline status for a specific browser compatibility data entry within a web-features feature, call getStatus with the web feature's ID and the BCD feature key as parameters, as shown below:

import { getStatus } from "compute-baseline";

getStatus("fetch", "api.Response.json");

Returns:

{
  baseline: 'high',
  baseline_low_date: '2017-03-27',
  baseline_high_date: '2019-09-27',
  support: {
    chrome: '42',
    chrome_android: '42',
    edge: '14',
    firefox: '39',
    firefox_android: '39',
    safari: '10.1',
    safari_ios: '10.3'
  }
}

Check support for a group of compat keys

Note: This example returns support data that has not received an editorial review. Do not use for presenting a Baseline status. See Limitations.

import { computeBaseline } from "compute-baseline";

computeBaseline({
  compatKeys: [
    "javascript.builtins.AsyncFunction",
    "javascript.builtins.AsyncFunction.AsyncFunction",
    "javascript.operators.async_function",
    "javascript.operators.await",
    "javascript.statements.async_function",
  ],
});

Returns:

{
  baseline: 'high',
  baseline_low_date: '2017-04-05',
  baseline_high_date: '2019-10-05',
  discouraged: false,
  support: Map(7) { … }
  toJSON: [Function: toJSON]
}

Use the toJSON() method to get a web-features-like plain JSON representation of the status.

Check support for a single support key

Note: This example returns support data that has not received an editorial review. Do not use for presenting a Baseline status. See Limitations.

Sometimes it can be helpful to know if parent features have less support than the specific feature you're checking (for example, the parent is behind a prefix or flag) when computing a status for a deeply-nested feature. This is typically most interesting when checking a single key. Use the withAncestors option:

import { computeBaseline } from "compute-baseline";

computeBaseline({
  compatKeys: ["api.Notification.body"],
  withAncestors: true,
});

Bring your own compatibility data

Note: This example returns support data that has not received an editorial review. Do not use for presenting a Baseline status. See Limitations.

If you want to use some other source of data (such as pre-release browser-compat-data), you can bring your own schema-compatible compat data.

import data from "some-parsed-json-file";
import { computeBaseline } from "compute-baseline";
import { Compat } from "compute-baseline/browser-compat-data";

const compat = new Compat(data);

computeBaseline(
  {
    compatKeys: ["css.properties.border-color"],
  },
  compat,
);

Helping out and getting help

compute-baseline 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.