By the W3C WebDX Community Group and contributors.

compute-baseline computes preliminary 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.

If you need authoritative Baseline statuses, check out the web-features package instead.

Don't use compute-baseline to generate publishable Baseline statuses for arbitrary web platform features. The results of compute-baseline invocations have not received editorial review. Strictly speaking, a Baseline status requires editorial review, so statuses generated by compute-baseline are tentative. If you need authoritative Baseline statuses, check out the web-features package instead.

You can use compute-baseline to explore possibilities or do error correction. For example, you might use compute-baseline to hide a Baseline status, when showing a broader feature's status might be misleading.

If you're not sure whether your application fits with the definition of Baseline, please file an issue.

To use this package, you'll need:

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

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

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.

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,
});

If you don't want to import @mdn/browser-compat-data as your data source, 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,
);

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.