Support json module resolution in file loader (#565)

Co-authored-by: Jake Bailey <5341706+jakebailey@users.noreply.github.com>

Author: frodi-karlsson

internal/compiler/fileloader.go

@@ -274,8 +274,13 @@ func (p *fileLoader) resolveImportsAndModuleAugmentations(file *ast.SourceFile)
 
 			// Don't add the file if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs')
 			// This may still end up being an untyped module -- the file won't be included but imports will be allowed.
-
-			shouldAddFile := resolution.IsResolved() && tspath.FileExtensionIsOneOf(resolvedFileName, []string{".ts", ".tsx", ".mts", ".cts"})
+			hasAllowedExtension := false
+			if p.compilerOptions.ResolveJsonModule.IsTrue() {
+				hasAllowedExtension = tspath.FileExtensionIsOneOf(resolvedFileName, tspath.SupportedTSExtensionsWithJsonFlat)
+			} else {
+				hasAllowedExtension = tspath.FileExtensionIsOneOf(resolvedFileName, tspath.SupportedTSExtensionsFlat)
+			}
+			shouldAddFile := resolution.IsResolved() && hasAllowedExtension
 			// TODO(ercornel): !!!: other checks on whether or not to add the file
 
 			if shouldAddFile {

internal/tspath/extension.go

@@ -33,6 +33,7 @@ var (
 	SupportedJSExtensionsFlat                = []string{ExtensionJs, ExtensionJsx, ExtensionMjs, ExtensionCjs}
 	AllSupportedExtensionsWithJson           = slices.Concat(AllSupportedExtensions, [][]string{{ExtensionJson}})
 	SupportedTSExtensionsWithJson            = slices.Concat(SupportedTSExtensions, [][]string{{ExtensionJson}})
+	SupportedTSExtensionsWithJsonFlat        = slices.Concat(SupportedTSExtensionsFlat, []string{ExtensionJson})
 )
 
 func ExtensionIsTs(ext string) bool {

testdata/baselines/reference/submodule/compiler/isolatedModules_resolveJsonModule.errors.txt

@@ -4,3 +4,7 @@
 import j = require("./j.json");
 >j : Symbol(j, Decl(a.ts, 0, 0))
 
+=== /j.json ===
+
+{}
+

testdata/baselines/reference/submodule/compiler/isolatedModules_resolveJsonModule.errors.txt.diff

@@ -4,3 +4,7 @@
 import * as j from "./j.json";
 >j : Symbol(j, Decl(a.ts, 0, 6))
 
+=== /j.json ===
+
+{}
+

testdata/baselines/reference/submodule/compiler/isolatedModules_resolveJsonModule.symbols

@@ -13,14 +13,31 @@ interface Foo {
 
 fn(data.foo);
 >fn : Symbol(fn, Decl(index.ts, 7, 13))
+>data.foo : Symbol(foo, Decl(data.json, 0, 1))
 >data : Symbol(data, Decl(index.ts, 0, 6))
+>foo : Symbol(foo, Decl(data.json, 0, 1))
 
 fn(data.foo); // <-- shouldn't error!
 >fn : Symbol(fn, Decl(index.ts, 7, 13))
+>data.foo : Symbol(foo, Decl(data.json, 0, 1))
 >data : Symbol(data, Decl(index.ts, 0, 6))
+>foo : Symbol(foo, Decl(data.json, 0, 1))
 
 function fn(arg: Foo[]) { }
 >fn : Symbol(fn, Decl(index.ts, 7, 13))
 >arg : Symbol(arg, Decl(index.ts, 9, 12))
 >Foo : Symbol(Foo, Decl(index.ts, 0, 31))
 
+=== data.json ===
+{
+    "foo": [
+>"foo" : Symbol(foo, Decl(data.json, 0, 1))
+      {
+        "bool": true,
+>"bool" : Symbol(bool, Decl(data.json, 2, 7))
+
+        "str": "123"
+>"str" : Symbol(str, Decl(data.json, 3, 21))
+      }
+    ]
+}

testdata/baselines/reference/submodule/compiler/isolatedModules_resolveJsonModule.symbols.diff

@@ -11,30 +11,35 @@
  fn(data.foo);
  >fn : Symbol(fn, Decl(index.ts, 7, 13))
 ->data.foo : Symbol("foo", Decl(data.json, 0, 1))
++>data.foo : Symbol(foo, Decl(data.json, 0, 1))
  >data : Symbol(data, Decl(index.ts, 0, 6))
 ->foo : Symbol("foo", Decl(data.json, 0, 1))
++>foo : Symbol(foo, Decl(data.json, 0, 1))
 
  fn(data.foo); // <-- shouldn't error!
  >fn : Symbol(fn, Decl(index.ts, 7, 13))
 ->data.foo : Symbol("foo", Decl(data.json, 0, 1))
++>data.foo : Symbol(foo, Decl(data.json, 0, 1))
  >data : Symbol(data, Decl(index.ts, 0, 6))
 ->foo : Symbol("foo", Decl(data.json, 0, 1))
++>foo : Symbol(foo, Decl(data.json, 0, 1))
 
  function fn(arg: Foo[]) { }
  >fn : Symbol(fn, Decl(index.ts, 7, 13))
- >arg : Symbol(arg, Decl(index.ts, 9, 12))
- >Foo : Symbol(Foo, Decl(index.ts, 0, 31))
- 
--=== data.json ===
--{
--    "foo": [
+@@= skipped -23, +23 lines =@@
+ === data.json ===
+ {
+     "foo": [
 ->"foo" : Symbol("foo", Decl(data.json, 0, 1))
--      {
--        "bool": true,
++>"foo" : Symbol(foo, Decl(data.json, 0, 1))
+       {
+         "bool": true,
 ->"bool" : Symbol("bool", Decl(data.json, 2, 7))
--
--        "str": "123"
++>"bool" : Symbol(bool, Decl(data.json, 2, 7))
+ 
+         "str": "123"
 ->"str" : Symbol("str", Decl(data.json, 3, 21))
--      }
--    ]
--}
++>"str" : Symbol(str, Decl(data.json, 3, 21))
+       }
+     ]
+ }

testdata/baselines/reference/submodule/compiler/isolatedModules_resolveJsonModule_strict_outDir_commonJs.errors.txt

@@ -8,5 +8,12 @@ console.log(foo.ios);
 >console.log : Symbol(log, Decl(lib.dom.d.ts, --, --))
 >console : Symbol(console, Decl(lib.dom.d.ts, --, --))
 >log : Symbol(log, Decl(lib.dom.d.ts, --, --))
+>foo.ios : Symbol(ios, Decl(foo.ios.json, 0, 1))
 >foo : Symbol(foo, Decl(index.ts, 0, 6))
+>ios : Symbol(ios, Decl(foo.ios.json, 0, 1))
 
+=== /foo.ios.json ===
+{
+	"ios": "platform ios"
+>"ios" : Symbol(ios, Decl(foo.ios.json, 0, 1))
+}

testdata/baselines/reference/submodule/compiler/isolatedModules_resolveJsonModule_strict_outDir_commonJs.errors.txt.diff

@@ -10,11 +10,14 @@
 ->log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
 ->foo.ios : Symbol("ios", Decl(foo.ios.json, 0, 1))
 +>log : Symbol(log, Decl(lib.dom.d.ts, --, --))
++>foo.ios : Symbol(ios, Decl(foo.ios.json, 0, 1))
  >foo : Symbol(foo, Decl(index.ts, 0, 6))
 ->ios : Symbol("ios", Decl(foo.ios.json, 0, 1))
++>ios : Symbol(ios, Decl(foo.ios.json, 0, 1))
 
--=== /foo.ios.json ===
--{
--	"ios": "platform ios"
+ === /foo.ios.json ===
+ {
+ 	"ios": "platform ios"
 ->"ios" : Symbol("ios", Decl(foo.ios.json, 0, 1))
--}
++>"ios" : Symbol(ios, Decl(foo.ios.json, 0, 1))
+ }