feat(typescript): add support for "jsx: preserve" compiler option

When tsc is instructed to preserve jsx, the emitted files have a .jsx
extension for .tsx and .jsx inputs, which means ts_project needs to be
aware of the option to properly define outputs.

packages/typescript/internal/ts_project.bzl

@@ -269,6 +269,7 @@ def _validate_options_impl(ctx):
         allow_js = ctx.attr.allow_js,
         declaration = ctx.attr.declaration,
         declaration_map = ctx.attr.declaration_map,
+        preserve_jsx = ctx.attr.preserve_jsx,
         composite = ctx.attr.composite,
         emit_declaration_only = ctx.attr.emit_declaration_only,
         source_map = ctx.attr.source_map,
@@ -296,6 +297,7 @@ validate_options = rule(
         "composite": attr.bool(),
         "declaration": attr.bool(),
         "declaration_map": attr.bool(),
+        "preserve_jsx": attr.bool(),
         "emit_declaration_only": attr.bool(),
         "extends": attr.label(allow_files = [".json"]),
         "incremental": attr.bool(),
@@ -312,10 +314,20 @@ def _is_ts_src(src, allow_js):
         return True
     return allow_js and (src.endswith(".js") or src.endswith(".jsx"))
 
-def _out_paths(srcs, outdir, rootdir, allow_js, ext):
+def _replace_ext(f, ext_map):
+    cur_ext = f[f.rindex("."):]
+    new_ext = ext_map.get(cur_ext)
+    if new_ext != None:
+        return new_ext
+    new_ext = ext_map.get("*")
+    if new_ext != None:
+        return new_ext
+    return None
+
+def _out_paths(srcs, outdir, rootdir, allow_js, ext_map):
     rootdir_replace_pattern = rootdir + "/" if rootdir else ""
     return [
-        _join(outdir, f[:f.rindex(".")].replace(rootdir_replace_pattern, "") + ext)
+        _join(outdir, f[:f.rindex(".")].replace(rootdir_replace_pattern, "") + _replace_ext(f, ext_map))
         for f in srcs
         if _is_ts_src(f, allow_js)
     ]
@@ -331,6 +343,7 @@ def ts_project_macro(
         declaration = False,
         source_map = False,
         declaration_map = False,
+        preserve_jsx = False,
         composite = False,
         incremental = False,
         emit_declaration_only = False,
@@ -551,6 +564,8 @@ def ts_project_macro(
             Instructs Bazel to expect a `.js.map` output for each `.ts` source.
         declaration_map: if the `declarationMap` bit is set in the tsconfig.
             Instructs Bazel to expect a `.d.ts.map` output for each `.ts` source.
+        preserve_jsx: if the `jsx` value is set to "preserve" in the tsconfig.
+            Instructs Bazel to expect a `.jsx` or `.jsx.map` output for each `.tsx` source.
         composite: if the `composite` bit is set in the tsconfig.
             Instructs Bazel to expect a `.tsbuildinfo` output and a `.d.ts` output for each `.ts` source.
         incremental: if the `incremental` bit is set in the tsconfig.
@@ -620,6 +635,7 @@ def ts_project_macro(
                 declaration = declaration,
                 source_map = source_map,
                 declaration_map = declaration_map,
+                preserve_jsx = preserve_jsx,
                 composite = composite,
                 incremental = incremental,
                 ts_build_info_file = ts_build_info_file,
@@ -660,13 +676,22 @@ def ts_project_macro(
     typing_maps_outs = []
 
     if not emit_declaration_only:
-        js_outs.extend(_out_paths(srcs, out_dir, root_dir, allow_js, ".js"))
+        exts = {
+            ".tsx": ".jsx",
+            ".jsx": ".jsx",
+            "*": ".js",
+        } if preserve_jsx else {"*": ".js"}
+        js_outs.extend(_out_paths(srcs, out_dir, root_dir, allow_js, exts))
     if source_map and not emit_declaration_only:
-        map_outs.extend(_out_paths(srcs, out_dir, root_dir, False, ".js.map"))
+        exts = {
+            ".tsx": ".jsx.map",
+            "*": ".js.map",
+        } if preserve_jsx else {"*": ".js.map"}
+        map_outs.extend(_out_paths(srcs, out_dir, root_dir, False, exts))
     if declaration or composite:
-        typings_outs.extend(_out_paths(srcs, typings_out_dir, root_dir, allow_js, ".d.ts"))
+        typings_outs.extend(_out_paths(srcs, typings_out_dir, root_dir, allow_js, {"*": ".d.ts"}))
     if declaration_map:
-        typing_maps_outs.extend(_out_paths(srcs, typings_out_dir, root_dir, allow_js, ".d.ts.map"))
+        typing_maps_outs.extend(_out_paths(srcs, typings_out_dir, root_dir, allow_js, {"*": ".d.ts.map"}))
 
     if not len(js_outs) and not len(typings_outs):
         fail("""ts_project target "//{}:{}" is configured to produce no outputs.

packages/typescript/internal/ts_project_options_validator.ts

@@ -64,6 +64,25 @@ function main([tsconfigPath, output, target, attrsStr]: string[]): 0|1 {
     }
   }
 
+  const jsxEmit: Record<ts.JsxEmit, string|undefined> =
+      {
+        [ts.JsxEmit.None]: 'none',
+        [ts.JsxEmit.Preserve]: 'preserve',
+        [ts.JsxEmit.React]: 'react',
+        [ts.JsxEmit.ReactNative]: 'react-native',
+      }
+
+  function
+  check_preserve_jsx() {
+    const attr = 'preserve_jsx'
+    const jsxVal = options['jsx'] as ts.JsxEmit
+    if ((jsxVal === ts.JsxEmit.Preserve) !== Boolean(attrs[attr])) {
+      failures.push(
+          `attribute ${attr}=${attrs[attr]} does not match compilerOptions.jsx=${jsxEmit[jsxVal]}`);
+      buildozerCmds.push(`set ${attr} ${jsxVal === ts.JsxEmit.Preserve ? 'True' : 'False'}`);
+    }
+  }
+
   check('allowJs', 'allow_js');
   check('declarationMap', 'declaration_map');
   check('emitDeclarationOnly', 'emit_declaration_only');
@@ -72,6 +91,7 @@ function main([tsconfigPath, output, target, attrsStr]: string[]): 0|1 {
   check('declaration');
   check('incremental');
   check('tsBuildInfoFile', 'ts_build_info_file');
+  check_preserve_jsx();
 
   if (failures.length > 0) {
     console.error(`ERROR: ts_project rule ${
@@ -98,6 +118,7 @@ function main([tsconfigPath, output, target, attrsStr]: string[]): 0|1 {
 // source_map:            ${attrs.source_map}
 // emit_declaration_only: ${attrs.emit_declaration_only}
 // ts_build_info_file:    ${attrs.ts_build_info_file}
+// preserve_jsx:          ${attrs.preserve_jsx}
 `,
       'utf-8');
   return 0;

packages/typescript/test/ts_project/jsx/BUILD.bazel

@@ -0,0 +1,38 @@
+load("@build_bazel_rules_nodejs//:index.bzl", "nodejs_test")
+load("//packages/typescript:index.bzl", "ts_project")
+
+# Ensure that a.js produces outDir/a.js, outDir/a.d.ts, and outDir/a.d.ts.map
+SRCS = [
+    "a.tsx",
+    "b.jsx",
+]
+
+ts_project(
+    name = "tsconfig",
+    srcs = SRCS,
+    allow_js = True,
+    declaration = True,
+    declaration_map = True,
+    out_dir = "out",
+    preserve_jsx = True,
+    source_map = True,
+)
+
+filegroup(
+    name = "types",
+    srcs = [":tsconfig"],
+    output_group = "types",
+)
+
+nodejs_test(
+    name = "test",
+    data = [
+        ":tsconfig",
+        ":types",
+    ],
+    entry_point = "verify-preserve.js",
+    templated_args = [
+        "$(locations :types)",
+        "$(locations :tsconfig)",
+    ],
+)

packages/typescript/test/ts_project/jsx/a.tsx

@@ -0,0 +1 @@
+export const A = <div>a</div>

packages/typescript/test/ts_project/jsx/b.jsx

@@ -0,0 +1 @@
+export const B = <div>b</div>

packages/typescript/test/ts_project/jsx/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "sourceMap": true,
+    "declaration": true,
+    "declarationMap": true,
+    "jsx": "preserve",
+    "types": []
+  }
+}

packages/typescript/test/ts_project/jsx/verify-preserve.js

@@ -0,0 +1,8 @@
+const assert = require('assert');
+
+const files = process.argv.slice(2);
+assert.ok(files.some(f => f.endsWith('out/a.d.ts')), 'Missing a.d.ts');
+assert.ok(files.some(f => f.endsWith('out/a.d.ts.map')), 'Missing a.d.ts.map');
+assert.ok(files.some(f => f.endsWith('out/a.jsx.map'), 'Missing a.jsx.map'));
+assert.ok(files.some(f => f.endsWith('out/a.jsx'), 'Missing a.jsx'));
+assert.ok(files.some(f => f.endsWith('out/b.jsx'), 'Missing b.jsx'));