internal/providers/js_providers.bzl

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"""Providers for interop between JS rules.

This file has to live in the built-in so that all rules can load() the providers
even if users haven't installed any of the packages/*

These providers allows rules to interoperate without knowledge
of each other.

You can think of a provider as a message bus.
A rule "publishes" a message as an instance of the provider, and some other rule
subscribes to these by having a (possibly transitive) dependency on the publisher.

## Debugging

Debug output is considered orthogonal to these providers.
Any output may or may not have user debugging affordances provided, such as
readable minification.
We expect that rules will have a boolean `debug` attribute, and/or accept the
`COMPILATION_MODE` environment variable.
Note that this means a given build either produces debug or non-debug output.
If users really need to produce both in a single build, they'll need two rules with
differing 'debug' attributes.
"""

JSNamedModuleInfo = provider(
    doc = """JavaScript files whose module name is self-contained.

For example named AMD/UMD or goog.module format.
These outputs should be named "foo.umd.js"
(note that renaming it from "foo.js" doesn't affect the module id)

Historical note: this was the typescript.es5_sources output.
""",
    fields = {
        "direct_sources": "Depset of direct JavaScript files and sourcemaps",
        "sources": "Depset of direct and transitive JavaScript files and sourcemaps",
    },
)

def js_named_module_info(sources, deps = []):
    """Constructs a JSNamedModuleInfo including all transitive sources from JSNamedModuleInfo providers in a list of deps.

    Returns a single JSNamedModuleInfo.
    """
    transitive_depsets = [sources]
    for dep in deps:
        if JSNamedModuleInfo in dep:
            transitive_depsets.append(dep[JSNamedModuleInfo].sources)

    return JSNamedModuleInfo(
        direct_sources = sources,
        sources = depset(transitive = transitive_depsets),
    )

JSEcmaScriptModuleInfo = provider(
    doc = """JavaScript files (and sourcemaps) that are intended to be consumed by downstream tooling.

They should use modern syntax and ESModules.
These files should typically be named "foo.mjs"

Historical note: this was the typescript.es6_sources output""",
    # TODO: should we require that these are ESModules with the mjs extension?
    fields = {
        "direct_sources": "Depset of direct JavaScript files and sourcemaps",
        "sources": "Depset of direct and transitive JavaScript files and sourcemaps",
    },
)

def js_ecma_script_module_info(sources, deps = []):
    """Constructs a JSEcmaScriptModuleInfo including all transitive sources from JSEcmaScriptModuleInfo providers in a list of deps.

    Returns a single JSEcmaScriptModuleInfo.
    """
    transitive_depsets = [sources]
    for dep in deps:
        if JSEcmaScriptModuleInfo in dep:
            transitive_depsets.append(dep[JSEcmaScriptModuleInfo].sources)

    return JSEcmaScriptModuleInfo(
        direct_sources = sources,
        sources = depset(transitive = transitive_depsets),
    )