diff --git a/.prettierignore b/.prettierignore
index 2fde4b5..5627bbe 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,2 +1,3 @@
 docs/*.md
 **/expected.js
+**/expected.cjs
diff --git a/docs/swc.md b/docs/swc.md
index 2b49512..c3d0bd5 100644
--- a/docs/swc.md
+++ b/docs/swc.md
@@ -34,8 +34,8 @@ for example to set your own output labels for `js_outs`.
 | <a id="swc_rule-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |  |
 | <a id="swc_rule-args"></a>args |  additional arguments to pass to swc cli, see https://swc.rs/docs/usage/cli   | List of strings | optional | [] |
 | <a id="swc_rule-data"></a>data |  runtime dependencies propagated to binaries that depend on this   | <a href="https://bazel.build/docs/build-ref.html#labels">List of labels</a> | optional | [] |
-| <a id="swc_rule-js_outs"></a>js_outs |  list of expected JavaScript output files   | List of labels | optional |  |
-| <a id="swc_rule-map_outs"></a>map_outs |  list of expected source map output files   | List of labels | optional |  |
+| <a id="swc_rule-js_outs"></a>js_outs |  list of expected JavaScript output files.<br><br>There must be one for each entry in srcs, and in the same order.   | List of labels | optional |  |
+| <a id="swc_rule-map_outs"></a>map_outs |  list of expected source map output files.<br><br>Can be empty, meaning no source maps should be produced. If non-empty, there must be one for each entry in srcs, and in the same order.   | List of labels | optional |  |
 | <a id="swc_rule-output_dir"></a>output_dir |  whether to produce a directory output rather than individual files   | Boolean | optional | False |
 | <a id="swc_rule-srcs"></a>srcs |  source files, typically .ts files in the source tree   | <a href="https://bazel.build/docs/build-ref.html#labels">List of labels</a> | required |  |
 | <a id="swc_rule-swc_cli"></a>swc_cli |  binary that executes the swc CLI   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | @aspect_rules_swc//swc:cli |
diff --git a/examples/custom_outs/BUILD.bazel b/examples/custom_outs/BUILD.bazel
new file mode 100644
index 0000000..c3e4438
--- /dev/null
+++ b/examples/custom_outs/BUILD.bazel
@@ -0,0 +1,30 @@
+load("@aspect_rules_swc//swc:swc.bzl", swc = "swc_rule")
+load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
+
+[
+    swc(
+        name = "transpile_" + format,
+        srcs = ["in.ts"],
+        args = [
+            "-C",
+            "module.type=" + format,
+        ],
+        js_outs = [format + "/out." + ("cjs" if format == "commonjs" else "js")],
+    )
+    for format in [
+        "commonjs",
+        "es6",
+    ]
+]
+
+diff_test(
+    name = "test_commonjs",
+    file1 = "commonjs/out.cjs",
+    file2 = "expected.cjs",
+)
+
+diff_test(
+    name = "test_es6",
+    file1 = "es6/out.js",
+    file2 = "expected.js",
+)
diff --git a/examples/custom_outs/expected.cjs b/examples/custom_outs/expected.cjs
new file mode 100755
index 0000000..87da5ca
--- /dev/null
+++ b/examples/custom_outs/expected.cjs
@@ -0,0 +1,10 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+exports.a = void 0;
+var a = "a";
+exports.a = a;
+
+
+//# sourceMappingURL=out.cjs.map
\ No newline at end of file
diff --git a/examples/custom_outs/expected.js b/examples/custom_outs/expected.js
new file mode 100644
index 0000000..d536c6b
--- /dev/null
+++ b/examples/custom_outs/expected.js
@@ -0,0 +1,4 @@
+export var a = "a";
+
+
+//# sourceMappingURL=out.js.map
\ No newline at end of file
diff --git a/examples/custom_outs/in.ts b/examples/custom_outs/in.ts
new file mode 100644
index 0000000..f6c1fdd
--- /dev/null
+++ b/examples/custom_outs/in.ts
@@ -0,0 +1 @@
+export const a: string = "a";
diff --git a/swc/private/swc.bzl b/swc/private/swc.bzl
index a8aa847..67f8845 100644
--- a/swc/private/swc.bzl
+++ b/swc/private/swc.bzl
@@ -17,8 +17,13 @@ _attrs = {
 }
 
 _outputs = {
-    "js_outs": attr.output_list(doc = "list of expected JavaScript output files"),
-    "map_outs": attr.output_list(doc = "list of expected source map output files"),
+    "js_outs": attr.output_list(doc = """list of expected JavaScript output files.
+
+There must be one for each entry in srcs, and in the same order."""),
+    "map_outs": attr.output_list(doc = """list of expected source map output files.
+
+Can be empty, meaning no source maps should be produced.
+If non-empty, there must be one for each entry in srcs, and in the same order."""),
 }
 
 def _impl(ctx):
@@ -60,12 +65,12 @@ def _impl(ctx):
     else:
         outputs.extend(ctx.outputs.js_outs)
         outputs.extend(ctx.outputs.map_outs)
-        for src in ctx.files.srcs:
-            js_out = ctx.actions.declare_file(paths.replace_extension(src.basename, ".js"), sibling = src)
+        for i, src in enumerate(ctx.files.srcs):
+            js_out = ctx.outputs.js_outs[i]
             inputs = [src] + ctx.toolchains["@aspect_rules_swc//swc:toolchain_type"].swcinfo.tool_files
             outs = [js_out]
             if source_maps:
-                outs.append(ctx.actions.declare_file(paths.replace_extension(src.basename, ".js.map"), sibling = src))
+                outs.append(ctx.outputs.map_outs[i])
 
             # Pass in the swcrc config if it is set
             if ctx.file.swcrc: