functionalscript · sergey-shandar · Aug 11, 2026 · Aug 11, 2026 · Aug 11, 2026 · Aug 11, 2026
diff --git a/AGENTS.md b/AGENTS.md
@@ -625,7 +625,7 @@ whenever that type changes.
 
 #### `StringMap` / `RequiredMap` / `OptionalMap` for string-keyed records
 
-Use the record types from `fjs/types/object/module.f.ts` for all string-keyed
+Use the record types from `fjs/types/object/types.ts` for all string-keyed
 record types. The key set picks the type:
 
 - **Open key set:** `StringMap<T>` is `{ readonly[k in string]?: T }` — any
@@ -653,7 +653,7 @@ a property of aliasing, not of any one definition — writing the record as a
 mapped type rather than a conditional one does not lift it.
 
 When iterating all defined entries of a `StringMap<T>`, use `definedEntries`
-from `fjs/types/object/module.f.ts` instead of `Object.entries`; use
+from `fjs/types/object/module.f.mjs` instead of `Object.entries`; use
 `definedValues` instead of `Object.values`.
 
 #### `flatMap` over a filtering type predicate

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -20,6 +20,19 @@ history.
 
 ## Unreleased
 
+- **BREAKING CHANGES:** `fjs/types/object`, `fjs/sul/level/literal`,
+  `fjs/sul/id`, `fjs/sul/level/hash`, `fjs/types/string_set`, and the
+  `module.f.ts` of `fjs/types/sorted_set` and `fjs/types/byte_set`
+  migrate to `.f.mjs`, splitting their public types into a sibling
+  `types.ts` — importers must use the `.f.mjs` specifier for runtime
+  values and the `types.ts` specifier for types
+  [#1484](https://github.com/functionalscript/functionalscript/pull/1484)
+- **BREAKING CHANGES:** `fjs/crypto/hmac`, `fjs/path`, and
+  `fjs/media/json/serializer` migrate from authored TypeScript
+  (`.f.ts`) to JSDoc-typed JavaScript (`.f.mjs`) under the stage-1
+  TypeScript-to-mjs migration — importers must use the `.f.mjs`
+  specifier
+  [#1484](https://github.com/functionalscript/functionalscript/pull/1484)
 - **BREAKING CHANGES:** every public type exported by an authored `.f.mjs`
   module moves to a sibling `types.ts` (31 modules, including `asserts`,
   `types/list`, `types/bit_vec`, `types/result`, `text`, `crypto/sha2`) —

diff --git a/fjs/bnf/data/module.f.ts b/fjs/bnf/data/module.f.ts
@@ -18,7 +18,8 @@ import {
     type Rule as FRule,
     type Sequence as FSequence,
 } from '../module.f.ts'
-import { definedEntries, type StringMap } from '../../types/object/module.f.ts'
+import { definedEntries } from '../../types/object/module.f.mjs'
+import type { StringMap } from '../../types/object/types.ts'
 
 /**
  * Encoded terminal range value used by BNF data rules.

diff --git a/fjs/bnf/data/proof.f.ts b/fjs/bnf/data/proof.f.ts
@@ -1,6 +1,6 @@
 import { stringify } from '../../media/json/module.f.ts'
 import { identity } from '../../types/function/module.f.mjs'
-import { sort } from '../../types/object/module.f.ts'
+import { sort } from '../../types/object/module.f.mjs'
 import { oneEncode, option, range, rangeDecode, repeat0Plus, set } from '../module.f.ts'
 import { classic, deterministic } from '../testlib.f.ts'
 import { emptyTagMap, type RuleSet, toData } from './module.f.ts'

diff --git a/fjs/bnf/descent/module.f.ts b/fjs/bnf/descent/module.f.ts
@@ -16,7 +16,7 @@
 import type { CodePoint } from '../../text/utf16/types.ts'
 import { rangeDecode, type TerminalRange } from '../module.f.ts'
 import { contains as rangeContains } from '../../types/range/module.f.mjs'
-import { definedEntries } from '../../types/object/module.f.ts'
+import { definedEntries } from '../../types/object/module.f.mjs'
 import { emptyTagMap, toData, type Rule as DataRule, type Sequence } from '../data/module.f.ts'
 import { type Rule as FRule } from '../module.f.ts'
 

diff --git a/fjs/bnf/ll1/module.f.ts b/fjs/bnf/ll1/module.f.ts
@@ -15,9 +15,11 @@ import { strictEqual } from '../../types/function/operator/module.f.mjs'
 import { toArray } from '../../types/list/module.f.mjs'
 import type { RangeMapArray } from '../../types/range_map/types.ts'
 import { rangeMap } from '../../types/range_map/module.f.mjs'
-import { contains, set, type StringSet } from '../../types/string_set/module.f.ts'
+import { contains, set } from '../../types/string_set/module.f.mjs'
+import type { StringSet } from '../../types/string_set/types.ts'
 import { rangeDecode } from '../module.f.ts'
-import { definedEntries, type StringMap } from '../../types/object/module.f.ts'
+import { definedEntries } from '../../types/object/module.f.mjs'
+import type { StringMap } from '../../types/object/types.ts'
 import { emptyTagMap, type EmptyTag, type RuleSet, toData } from '../data/module.f.ts'
 import { type Rule as FRule } from '../module.f.ts'
 

diff --git a/fjs/bnf/module.f.ts b/fjs/bnf/module.f.ts
@@ -10,7 +10,8 @@
 import type { Tuple } from '../types/array/types.ts'
 
 import { codePointListToString, stringToCodePointList } from '../text/utf16/module.f.mjs'
-import { definedValues, type StringMap } from '../types/object/module.f.ts'
+import { definedValues } from '../types/object/module.f.mjs'
+import type { StringMap } from '../types/object/types.ts'
 import { isTuple } from '../types/array/module.f.mjs'
 import { map, toArray, repeat as listRepeat } from '../types/list/module.f.mjs'
 import { contains } from '../types/range/module.f.mjs'

diff --git a/fjs/cas/evo/module.f.ts b/fjs/cas/evo/module.f.ts
@@ -53,7 +53,8 @@ import { decodeText, encodeText, dialect, checkReferences, isHash, type LockMap,
 import type { Ok, Result } from '../../types/result/types.ts'
 import { ok, error } from '../../types/result/module.f.mjs'
 import { nonEmpty, empty as elEmpty } from '../../effects/list/module.f.ts'
-import { at, definedEntries, type StringMap } from '../../types/object/module.f.ts'
+import { at, definedEntries } from '../../types/object/module.f.mjs'
+import type { StringMap } from '../../types/object/types.ts'
 import { unwrap } from '../../types/nullable/module.f.mjs'
 import type { Vec } from '../../types/bit_vec/types.ts'
 import { isNotFound, type IoResult } from '../../effects/node/module.f.ts'

diff --git a/fjs/cas/module.f.ts b/fjs/cas/module.f.ts
@@ -5,7 +5,7 @@
  */
 import type { Sha2, State as Sha2State } from '../crypto/sha2/types.ts'
 import { sha256 } from '../crypto/sha2/module.f.mjs'
-import { join, normalize, parse } from '../path/module.f.ts'
+import { join, normalize, parse } from '../path/module.f.mjs'
 import type { Vec } from '../types/bit_vec/types.ts'
 import { empty, length, maxLength, maxLengthBytes, msb, vec } from '../types/bit_vec/module.f.mjs'
 import { cBase32ToVec, vecToCBase32 } from '../basen/cbase32/module.f.mjs'

diff --git a/fjs/cas/proof.f.ts b/fjs/cas/proof.f.ts
@@ -8,7 +8,7 @@ import { mkdir, writeFile, rm, readFile, type ReadFile, type WriteFile, type Rm,
 import type { Ok } from '../types/result/types.ts'
 import { error, ok } from '../types/result/module.f.mjs'
 import { emptyState, virtual } from '../effects/node/virtual/module.f.ts'
-import { join } from '../path/module.f.ts'
+import { join } from '../path/module.f.mjs'
 import { nonEmpty, empty, type List } from '../effects/list/module.f.ts'
 import { assert, assertEq, assertNotNullish } from '../asserts/module.f.mjs'
 

diff --git a/fjs/cas/todo/shard-dir-helper.md b/fjs/cas/todo/shard-dir-helper.md
@@ -23,7 +23,7 @@ how a key becomes segments, and `publish` separately assumes "the last
 segment is the file name". A layout change (e.g. a different shard depth)
 would have to be caught in both places, and the `mkdir(dstDir,
 { recursive: true })` that follows depends on the fragile re-parse.
-`fjs/path/module.f.ts` also has no `dirname`/`parent` helper, so the
+`fjs/path/module.f.mjs` also has no `dirname`/`parent` helper, so the
 open-coded `parse(x).slice(0, -1)` is the only way to express this today.
 
 ### Proposal
@@ -49,7 +49,7 @@ export const toPath = (key: Vec): string => {
 
 `publish` then uses `const { dir } = shard(hash)` and
 `mkdir(join(path, dir), { recursive: true })` — no re-parse, no `slice`.
-Alternative considered: a general `dirname` in `fjs/path/module.f.ts`; the
+Alternative considered: a general `dirname` in `fjs/path/module.f.mjs`; the
 `shard` form is preferred because the CAS write path should not know how a
 shard path decomposes, and no second `dirname` consumer exists yet.
 

diff --git a/fjs/ci/proof.f.ts b/fjs/ci/proof.f.ts
@@ -10,7 +10,7 @@ import type { State } from '../effects/node/virtual/module.f.ts'
 import { emptyState, virtual, type Dir } from '../effects/node/virtual/module.f.ts'
 import { parse as jsonParse } from '../media/json/module.f.ts'
 import { unwrap } from '../types/result/module.f.mjs'
-import { definedValues } from '../types/object/module.f.ts'
+import { definedValues } from '../types/object/module.f.mjs'
 
 const hasRun = (cmd: string) => (gha: GitHubAction): boolean =>
     definedValues(gha.jobs).some(job => job.steps.some(step => step.run?.includes(cmd)))

diff --git a/fjs/cli/module.f.ts b/fjs/cli/module.f.ts
@@ -1,6 +1,6 @@
 import { errorExit, log, type NodeOp, type NodeProgramOptions, type Write } from '../effects/node/module.f.ts'
 import { pure, step, type Effect } from '../effects/module.f.ts'
-import { at, fromEntries } from '../types/object/module.f.ts'
+import { at, fromEntries } from '../types/object/module.f.mjs'
 
 type Handler<O extends NodeOp> = (options: NodeProgramOptions) => Effect<O, number>
 

diff --git a/fjs/crypto/hmac/module.f.ts → fjs/crypto/hmac/module.f.mjs b/fjs/crypto/hmac/module.f.ts → fjs/crypto/hmac/module.f.mjs
@@ -9,7 +9,7 @@
  * @example
  *
  * ```ts
- * import { vec } from '../../types/bit_vec/module.f.ts'
+ * import { vec } from '../../types/bit_vec/module.f.mjs'
  * import { msbUtf8 } from '../../text/module.f.mjs'
  * import { sha256 } from '../sha2/module.f.mjs'
  *
@@ -18,9 +18,9 @@
  * ```
  */
 
-import type { Vec, Reduce } from '../../types/bit_vec/types.ts'
+/** @import { Vec, Reduce } from '../../types/bit_vec/types.ts' */
 import { length, msb, vec, vec8, repeat } from '../../types/bit_vec/module.f.mjs'
-import type { Sha2 } from '../sha2/types.ts'
+/** @import { Sha2 } from '../sha2/types.ts' */
 import { computeSync } from '../sha2/module.f.mjs'
 
 const { concat, xor } = msb
@@ -38,11 +38,11 @@ const iPad = vec8(0x36n)
 /**
  * Generates an HMAC (Hash-based Message Authentication Code) using the specified hash function.
  *
- * @param hashFunc - The hash function implementation to use.
- * @returns - A function that takes a key and returns another function
+ * @param {Sha2} hashFunc - The hash function implementation to use.
+ * @returns {Reduce} A function that takes a key and returns another function
  * that takes a message and computes the HMAC.
  */
-export const hmac = (hashFunc: Sha2): Reduce => {
+export const hmac = hashFunc => {
     const { blockLength } = hashFunc
     const p = repeat(blockLength >> 3n)
     const ip = p(iPad)
@@ -52,9 +52,10 @@ export const hmac = (hashFunc: Sha2): Reduce => {
         const k1 = length(k) > blockLength ? c([k]) : k
         const k2 = concat(k1)(vec(blockLength - length(k1))(0n))
         const xk2 = xor(k2)
-        const f = (p: Vec) => {
+        /** @type {(p: Vec) => (msg: Vec) => Vec} */
+        const f = p => {
             const x = xk2(p)
-            return (msg: Vec) => c([x, msg])
+            return msg => c([x, msg])
         }
         const fip = f(ip)
         const fop = f(op)

diff --git a/fjs/crypto/hmac/proof.f.ts → fjs/crypto/hmac/proof.f.mjs b/fjs/crypto/hmac/proof.f.ts → fjs/crypto/hmac/proof.f.mjs
@@ -2,7 +2,7 @@ import { assertEq } from '../../asserts/module.f.mjs'
 import { utf8 } from '../../text/module.f.mjs'
 import { uint, vec } from '../../types/bit_vec/module.f.mjs'
 import { sha256, sha384, sha512 } from '../sha2/module.f.mjs'
-import { hmac } from './module.f.ts'
+import { hmac } from './module.f.mjs'
 
 export const proof = {
     example: () => {

diff --git a/fjs/crypto/sign/module.f.ts b/fjs/crypto/sign/module.f.ts
@@ -8,7 +8,7 @@ import type { Tuple } from '../../types/array/types.ts'
 import { bitLength, divUp8, roundUp8 } from '../../types/bigint/module.f.mjs'
 import type { Vec } from '../../types/bit_vec/types.ts'
 import { empty, length, msb, repeat, unpack, vec, vec8 } from '../../types/bit_vec/module.f.mjs'
-import { hmac } from '../hmac/module.f.ts'
+import { hmac } from '../hmac/module.f.mjs'
 import type { Curve } from '../secp/types.ts'
 import type { Sha2 } from '../sha2/types.ts'
 import { computeSync } from '../sha2/module.f.mjs'

diff --git a/fjs/crypto/sign/proof.f.ts b/fjs/crypto/sign/proof.f.ts
@@ -2,7 +2,7 @@ import { utf8 } from "../../text/module.f.mjs"
 import type { Tuple } from "../../types/array/types.ts"
 import type { Vec } from "../../types/bit_vec/types.ts"
 import { empty, msb, repeat, vec, vec8 } from "../../types/bit_vec/module.f.mjs"
-import { hmac } from "../hmac/module.f.ts"
+import { hmac } from "../hmac/module.f.mjs"
 import type { Curve } from "../secp/types.ts"
 import { secp192r1, secp256r1, secp384r1, secp521r1 } from "../secp/module.f.mjs"
 import type { Sha2 } from "../sha2/types.ts"

diff --git a/fjs/dev/module.f.ts b/fjs/dev/module.f.ts
@@ -14,10 +14,10 @@ import {
     type Readdir
 } from '../effects/node/module.f.ts'
 import { cmp as strCmp } from '../types/string/module.f.mjs'
-import type { StringMap } from '../types/object/module.f.ts'
+import type { StringMap } from '../types/object/types.ts'
 import { unwrap } from '../types/result/module.f.mjs'
 import { pure, step, type Effect } from '../effects/module.f.ts'
-import { join, relativize, toPosix } from '../path/module.f.ts'
+import { join, relativize, toPosix } from '../path/module.f.mjs'
 import { assert, assertEq } from '../asserts/module.f.mjs'
 import { emptyState, virtual, type Dir } from '../effects/node/virtual/module.f.ts'
 

diff --git a/fjs/dev/todo/dev-allfiles-flatmap.md b/fjs/dev/todo/dev-allfiles-flatmap.md
@@ -32,7 +32,7 @@ zero or one effect, which is exactly the `flatMap` shape. The repeated
 `result = [...result, x]` is also O(n²) in entry count.
 
 Secondary: line 82 destructures `const { fromEntries } = Object` while
-`AGENTS.md` mandates the typed helpers from `fjs/types/object/module.f.ts`
+`AGENTS.md` mandates the typed helpers from `fjs/types/object/module.f.mjs`
 for string-keyed maps (`fjs/cli` already imports from there).
 
 ### Proposal
@@ -50,14 +50,14 @@ readdir(p, {}).step(d => all(...unwrap(d).flatMap(i => {
 
 No `let`, no `continue`, no accumulator reassignment; the 0-or-1 mapping per
 entry is explicit. Also replace the `Object.fromEntries` destructuring with
-the appropriate helper from `fjs/types/object/module.f.ts` (or file a
+the appropriate helper from `fjs/types/object/module.f.mjs` (or file a
 follow-up if no typed `fromEntries` exists there yet).
 
 ### Tasks
 
 - [ ] Rewrite the `load` body with `flatMap` as above.
 - [ ] Replace `const { fromEntries } = Object` with the typed equivalent
-      from `fjs/types/object/module.f.ts`, adding one there if missing (it
+      from `fjs/types/object/module.f.mjs`, adding one there if missing (it
       has consumers waiting: this module and future map-builders).
 - [ ] Run `npx tsc` and `fjs t`.
 

diff --git a/fjs/djs/ast/module.f.ts b/fjs/djs/ast/module.f.ts
@@ -7,7 +7,7 @@ import type { Primitive, Array, Unknown } from '../module.f.ts'
 import type { List } from '../../types/list/types.ts'
 import { concat, fold, last, map, take, toArray } from '../../types/list/module.f.mjs'
 import type { Entry } from '../../types/ordered_map/types.ts'
-import { fromEntries } from '../../types/object/module.f.ts'
+import { fromEntries } from '../../types/object/module.f.mjs'
 
 const { entries } = Object
 

diff --git a/fjs/djs/ast/proof.f.ts b/fjs/djs/ast/proof.f.ts
@@ -1,4 +1,4 @@
-import { sort } from '../../types/object/module.f.ts'
+import { sort } from '../../types/object/module.f.mjs'
 import { run } from './module.f.ts'
 import { stringifyAsTree } from '../serializer/module.f.ts'
 import { assertEq } from '../../asserts/module.f.mjs'

diff --git a/fjs/djs/module.f.ts b/fjs/djs/module.f.ts
@@ -6,7 +6,7 @@
 import type { Primitive as JsonPrimitive } from '../media/json/module.f.ts'
 import { transpile } from './transpiler/module.f.ts'
 import { stringify, stringifyAsTree } from './serializer/module.f.ts'
-import { sort } from '../types/object/module.f.ts'
+import { sort } from '../types/object/module.f.mjs'
 import { type Effect, pure, step } from '../effects/module.f.ts'
 import {
     writeUtf8File,

diff --git a/fjs/djs/parser/module.f.ts b/fjs/djs/parser/module.f.ts
@@ -11,7 +11,7 @@ import type { Fold } from '../../types/function/operator/types.ts'
 import type { DjsToken, DjsTokenWithMetadata } from '../tokenizer/module.f.ts'
 import { setReplace, at } from '../../types/ordered_map/module.f.mjs'
 import type { OrderedMap } from '../../types/ordered_map/types.ts'
-import { fromMap } from '../../types/object/module.f.ts'
+import { fromMap } from '../../types/object/module.f.mjs'
 import type { AstArray, AstConst, AstModule, AstModuleRef } from '../ast/module.f.ts'
 import type { TokenMetadata } from '../../js/tokenizer/module.f.ts'
 import { assertEq } from '../../asserts/module.f.mjs'

diff --git a/fjs/djs/parser/proof.f.ts b/fjs/djs/parser/proof.f.ts
@@ -1,7 +1,7 @@
 import { parseFromTokens } from './module.f.ts'
 import { tokenize, type DjsTokenWithMetadata } from '../tokenizer/module.f.ts'
 import { toArray } from '../../types/list/module.f.mjs'
-import { sort } from '../../types/object/module.f.ts'
+import { sort } from '../../types/object/module.f.mjs'
 import { stringToList } from '../../text/utf16/module.f.mjs'
 import { stringifyAsTree } from '../serializer/module.f.ts'
 import { stringify } from '../../media/json/module.f.ts'

diff --git a/fjs/djs/serializer/module.f.ts b/fjs/djs/serializer/module.f.ts
@@ -5,15 +5,15 @@
  */
 import type { Unknown, Object } from '../module.f.ts'
 import type { Fold } from '../../types/function/operator/types.ts'
-import type { Entry as ObjectEntry } from '../../types/object/module.f.ts'
+import type { Entry as ObjectEntry } from '../../types/object/types.ts'
 import { fold } from '../../types/list/module.f.mjs'
 import { concat } from '../../types/string/module.f.mjs'
 import type { List } from '../../types/list/types.ts'
 import { flat, flatMap, map, concat as listConcat } from '../../types/list/module.f.mjs'
 const { entries } = Object
 import { compose, fn } from '../../types/function/module.f.mjs'
 import { serialize as bigintSerialize } from '../../types/bigint/module.f.mjs'
-import { objectWrap, arrayWrap, stringSerialize, numberSerialize, nullSerialize, boolSerialize } from '../../media/json/serializer/module.f.ts'
+import { objectWrap, arrayWrap, stringSerialize, numberSerialize, nullSerialize, boolSerialize } from '../../media/json/serializer/module.f.mjs'
 
 const colon = [':']
 

diff --git a/fjs/djs/serializer/proof.f.ts b/fjs/djs/serializer/proof.f.ts
@@ -1,5 +1,5 @@
 import { countRefs, stringify, stringifyAsTree } from './module.f.ts'
-import { sort } from '../../types/object/module.f.ts'
+import { sort } from '../../types/object/module.f.mjs'
 import { identity } from '../../types/function/module.f.mjs'
 import { setProperty } from '../../media/json/module.f.ts'
 import { assertEq } from '../../asserts/module.f.mjs'

diff --git a/fjs/djs/todo/157.md b/fjs/djs/todo/157.md
@@ -107,7 +107,7 @@ Each defines the identical closure cluster: `propertySerialize`
 the recursive `f` switching on `typeof`, and
 `arraySerialize = compose(map(f))(arrayWrap)`. The serializer already imports
 its primitives (`stringSerialize`, `objectWrap`, `arrayWrap`, …) from
-`fjs/media/json/serializer/module.f.ts`, so the leaves are shared; only the walker was
+`fjs/media/json/serializer/module.f.mjs`, so the leaves are shared; only the walker was
 copied.
 
 The deltas:

diff --git a/fjs/djs/todo/663-json-djs-tree-type.md b/fjs/djs/todo/663-json-djs-tree-type.md
@@ -111,5 +111,5 @@ serialization behavior.
 - [197](./197.md) — extracts traversal over the same `Unknown` shape.
 - `fjs/media/json/module.f.ts` — current JSON recursive type aliases.
 - `fjs/djs/module.f.ts` — current DJS recursive type aliases.
-- `fjs/media/json/serializer/module.f.ts` — currently has no separate recursive
+- `fjs/media/json/serializer/module.f.mjs` — currently has no separate recursive
   generic value aliases and therefore is not part of this migration.
diff --git a/fjs/djs/tokenizer/module.f.ts b/fjs/djs/tokenizer/module.f.ts
@@ -59,7 +59,7 @@ import { contains } from "../../types/range/module.f.mjs"
 import type { List } from "../../types/list/types.ts"
 import { concat, empty, filter, flat, flatMap, fold, map, stateScan, toArray } from "../../types/list/module.f.mjs"
 import { stringifyAsTree } from "../serializer/module.f.ts"
-import { sort } from "../../types/object/module.f.ts"
+import { sort } from "../../types/object/module.f.mjs"
 import type { Unknown } from "../module.f.ts"
 
 // Builds the single-token grammar that jsGrammar's whole-file `tokens` rule repeats.

diff --git a/fjs/djs/tokenizer/proof.f.ts b/fjs/djs/tokenizer/proof.f.ts
@@ -4,7 +4,7 @@ import { toArray } from '../../types/list/module.f.mjs'
 import { jsGrammar, tokenizeString, descentParserCpOnly, tokenizeJs, tokenize } from './module.f.ts'
 import { assert, assertEq } from '../../asserts/module.f.mjs'
 import { stringifyAsTree } from '../serializer/module.f.ts'
-import { sort } from '../../types/object/module.f.ts'
+import { sort } from '../../types/object/module.f.mjs'
 import type { Unknown } from '../module.f.ts'
 
 // DjsTokenWithMetadata carries bigint fields (bf, bigint value) that JSON.stringify can't

diff --git a/fjs/djs/transpiler/module.f.ts b/fjs/djs/transpiler/module.f.ts
@@ -12,7 +12,7 @@ import { tokenize } from '../tokenizer/module.f.ts'
 import { setReplace, at } from '../../types/ordered_map/module.f.mjs'
 import type { OrderedMap } from '../../types/ordered_map/types.ts'
 import { stringToList } from '../../text/utf16/module.f.mjs'
-import { concat as pathConcat } from '../../path/module.f.ts'
+import { concat as pathConcat } from '../../path/module.f.mjs'
 import { type ParseError, parseFromTokens } from '../parser/module.f.ts'
 import { run, type AstModule } from '../ast/module.f.ts'
 import { type Effect, foldStep, pure, step } from '../../effects/module.f.ts'