The Require filter supports Ruby-style require and require_relative statements. require function calls in expressions are left alone.

If the esm filter is used and the code being required contains export statements (either explicitly or via the autoexports option), then the require statement will be replaced with an import statement referencing the top level classes, modules, constants, and methods defined in that source.

If the require_recursive option is specified, then all symbols defined by all sources referenced by the transitive closure of all requires defined by that source.

If no exports are found, the required file is converted to JavaScript and expanded inline.

Next: Return