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This is not aiming to implement APIs that are missing on a given Babel version, but it is meant to provide clear error messages if a plugin is run on a version of Babel that doesn't have the APIs that the plugin is trying to use.

Every one of Babel's core plugins and presets will use this module, and ideally because of that its size should be kept to a minimum because this may or may not be deduplicated when installed.


import { declare } from "@babel/helper-plugin-utils";

export default declare((api, options, dirname) => {
return {};

What this does

Currently, this plugin provides a few services to ensure that plugins function well enough to throw useful errors.

options is always passed

Babel 6 does not pass a second parameter. This frequently means that plugins written for Babel 7 that use options will attempt to destructure options out of an undefined value. By supplying the default, we avoid that risk.

api.assertVersion always exists

Babel 6 and early betas of Babel 7 do not have assertVersion, so this wrapper ensures that it exists and throws a useful error message when not supplied by Babel itself.