This allows importing the library directly from an ESM, without requiring a build step. One change was required for a test to pass in index.runtime.js - a copy of the runtime module object is made to allow overriding checkRevision (ESMs don't allow modifying import objects). The source-map module is replaced via subpath imports rather than via runtime checking since require is not available in a ESM.

Before creating a pull-request, please check https://github.com/handlebars-lang/handlebars.js/blob/master/CONTRIBUTING.md first.

Generally we like to see pull requests that

• Please don't start pull requests for security issues. Instead, file a report at https://www.npmjs.com/advisories/report?package=handlebars
• Maintain the existing code style
• Are focused on a single change (i.e. avoid large refactoring or style adjustments in untouched code if not the primary goal of the pull request)
• Have good commit messages
• Have tests
• Have the typings (types/index.d.ts) updated on every API change. If you need help, updating those, please mention that in the PR description.
• Don't significantly decrease the current code coverage (see coverage/lcov-report/index.html)
• Currently, the 4.x-branch contains the latest version. Please target that branch in the PR.