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 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.
