This commit adds CJS/ESM interoperability when running in --compat mode.
Before executing files, they are analyzed and all CommonJS modules are
transformed on the fly to a ES modules. This is done by utilizing analyze_cjs()
functionality from deno_ast. After discovering exports and reexports, an ES
module is rendered and saved in memory for later use.
There's a caveat that all files ending with ".js" extension are considered as
CommonJS modules (unless there's a related "package.json" with "type": "module").
This commit adds proper support for import assertions and JSON modules.
Implementation of "core/modules.rs" was changed to account for multiple possible
module types, instead of always assuming that the code is an "ES module". In
effect "ModuleMap" now has knowledge about each modules' type (stored via
"ModuleType" enum). Module loading pipeline now stores information about
expected module type for each request and validates that expected type matches
discovered module type based on file's "MediaType".
Relevant tests were added to "core/modules.rs" and integration tests,
additionally multiple WPT tests were enabled.
There are still some rough edges in the implementation and not all WPT were
enabled, due to:
a) unclear BOM handling in source code by "FileFetcher"
b) design limitation of Deno's "FileFetcher" that doesn't download the same
module multiple times in a single run
Co-authored-by: Kitson Kelly <me@kitsonkelly.com>
This commit introduces "ProcState::maybe_resolver" field, which
stores a single instance of resolver for the whole lifetime of the
process, instead of creating these resolvers for each creation
of module graph. As a result, this resolver can be used in fallback
case where graph is not constructed (REPL, loading modules using
"require") unifying resolution logic.
This commit integrates import map and "classic" resolutions in
the "--compat" mode when using ES modules; in effect
"http:", "https:" and "blob:" imports now work in compat mode.
The algorithm works as follows:
1. If there's an import map, try to resolve using it and if succeeded
return the specifier
2. Try to resolve using "Node ESM resolution", and if succeeded return
the specifier
3. Fall back to regular ESM resolution
This commit adds CJS and ESM Node resolvers to the "--compat" mode.
The functionality is spread across "cli/compat" module and Node compatibility
layer in "deno_std/node"; this stems from the fact that ES module resolution
can only be implemented in Rust as it needs to directly integrated with
"deno_core"; however "deno_std/node" already provided CJS module resolution.
Currently this resolution is only active when running a files using
"deno run --compat --unstable <filename>", and is not available in other
subcommands, which will be changed in follow up commits.
Returns empty values in case of errors, source lines are non-essential anyway. These errors can happen e.g. when source files change at runtime. A warning is also printed to help us track when it happens in unexpected cases besides this.
This commit adds automatic injection of Node globals when "--compat" flag
is present.
This is done by executing "https://deno.land/std/node/global.ts" as a "side module",
before main module is executed.
This commit makes "--compat" required to be used with "--unstable" flag, as some
of Node globals require unstable Deno APIs.
This commit adds "--compat" flag. When the flag is passed a set of mappings for
built-in Node modules is injected into the import map. If user doesn't
explicitly provide an import map (using "--import-map" flag) then a map is
created on the fly. If there are already existing mappings in import map that
would clash with built-in Node modules a set of diagnostics is printed to the
terminal with suggestions how to proceed.
