feat(esbuild): add 'sourcemap' option to configure sourcemap generation

packages/esbuild/esbuild.bzl

@@ -54,7 +54,12 @@ def _esbuild_impl(ctx):
     args = ctx.actions.args()
 
     args.add("--bundle", entry_point.path)
-    args.add("--sourcemap")
+
+    if len(ctx.attr.sourcemap) > 0:
+        args.add_joined(["--sourcemap", ctx.attr.sourcemap], join_with = "=")
+    else:
+        args.add("--sourcemap")
+
     args.add("--preserve-symlinks")
     args.add_joined(["--platform", ctx.attr.platform], join_with = "=")
     args.add_joined(["--target", ctx.attr.target], join_with = "=")
@@ -87,8 +92,13 @@ def _esbuild_impl(ctx):
         args.add_joined(["--outdir", js_out.path], join_with = "=")
     else:
         js_out = ctx.outputs.output
+        outputs.append(js_out)
+
         js_out_map = ctx.outputs.output_map
-        outputs.extend([js_out, js_out_map])
+        if ctx.attr.sourcemap != "inline":
+            if js_out_map == None:
+                fail("output_map must be specified if sourcemap is not set to 'inline'")
+            outputs.append(js_out_map)
 
         if ctx.attr.format:
             args.add_joined(["--format", ctx.attr.format], join_with = "=")
@@ -214,6 +224,14 @@ See https://esbuild.github.io/api/#splitting for more details
 See https://esbuild.github.io/api/#platform for more details
             """,
         ),
+        "sourcemap": attr.string(
+            values = ["external", "inline", "both"],
+            mandatory = False,
+            doc = """Defines where sourcemaps are output and how they are included in the bundle. By default, a separate `.js.map` file is generated and referenced by the bundle. If 'external', a separate `.js.map` file is generated but not referenced by the bundle. If 'inline', a sourcemap is generated and its contents are inlined into the bundle (and no external sourcemap file is created). If 'both', a sourcemap is inlined and a `.js.map` file is created.
+
+See https://esbuild.github.io/api/#sourcemap for more details
+            """,
+        ),
         "sources_content": attr.bool(
             mandatory = False,
             default = False,
@@ -270,9 +288,13 @@ def esbuild_macro(name, output_dir = False, **kwargs):
             **kwargs
         )
     else:
+        output_map = None
+        sourcemap = kwargs.get("sourcemap", None)
+        if sourcemap != "inline":
+            output_map = "%s.js.map" % name
         esbuild(
             name = name,
             output = "%s.js" % name,
-            output_map = "%s.js.map" % name,
+            output_map = output_map,
             **kwargs
         )

packages/esbuild/test/sourcemap/BUILD.bazel

@@ -0,0 +1,55 @@
+load("//packages/esbuild/test:tests.bzl", "esbuild")
+load("//packages/jasmine:index.bzl", "jasmine_node_test")
+load("//packages/typescript:index.bzl", "ts_library")
+
+ts_library(
+    name = "main",
+    srcs = [
+        "main.ts",
+    ],
+    deps = [
+        "@npm//@types/node",
+    ],
+)
+
+esbuild(
+    name = "bundle_default",
+    args = ["--keep-names"],
+    entry_point = "main.ts",
+    deps = [":main"],
+)
+
+esbuild(
+    name = "bundle_inline",
+    args = ["--keep-names"],
+    entry_point = "main.ts",
+    sourcemap = "inline",
+    deps = [":main"],
+)
+
+esbuild(
+    name = "bundle_external",
+    args = ["--keep-names"],
+    entry_point = "main.ts",
+    sourcemap = "external",
+    deps = [":main"],
+)
+
+esbuild(
+    name = "bundle_both",
+    args = ["--keep-names"],
+    entry_point = "main.ts",
+    sourcemap = "both",
+    deps = [":main"],
+)
+
+jasmine_node_test(
+    name = "bundle_test",
+    srcs = ["bundle_test.js"],
+    data = [
+        ":bundle_both",
+        ":bundle_default",
+        ":bundle_external",
+        ":bundle_inline",
+    ],
+)

packages/esbuild/test/sourcemap/bundle_test.js

@@ -0,0 +1,62 @@
+const {readFileSync, exists} = require('fs');
+const path = require('path');
+
+const helper = require(process.env.BAZEL_NODE_RUNFILES_HELPER);
+const locationBase = 'build_bazel_rules_nodejs/packages/esbuild/test/sourcemap/';
+
+// Location for :bundle_default
+const bundleDefaultLocation = helper.resolve(path.join(locationBase, 'bundle_default.js'));
+const bundleDefaultSourcemapLocation =
+    helper.resolve(path.join(locationBase, 'bundle_default.js.map'));
+
+// Location for :bundle_inline
+const bundleInlineLocation = helper.resolve(path.join(locationBase, 'bundle_inline.js'));
+
+// Location for :bundle_external
+const bundleExternalLocation = helper.resolve(path.join(locationBase, 'bundle_external.js'));
+const bundleExternalSourcemapLocation =
+    helper.resolve(path.join(locationBase, 'bundle_external.js.map'));
+
+// Location for :bundle_both
+const bundleBothLocation = helper.resolve(path.join(locationBase, 'bundle_both.js'));
+const bundleBothSourcemapLocation = helper.resolve(path.join(locationBase, 'bundle_both.js.map'));
+
+describe('esbuild sourcemap', () => {
+  it('creates an external sourcemap by default', () => {
+    const sourcemap = readFileSync(bundleDefaultSourcemapLocation, {encoding: 'utf8'});
+    expect(sourcemap).toContain(
+        '"sources": ["../../../../../../../packages/esbuild/test/sourcemap/main.ts"]');
+  });
+
+  it('does not inline the sourcemap by default', () => {
+    const bundle = readFileSync(bundleDefaultLocation, {encoding: 'utf8'});
+    expect(bundle).toContain('//# sourceMappingURL=bundle_default.js.map');
+  });
+
+  it('inlines the sourcemap when set to \'inline\'', () => {
+    const bundle = readFileSync(bundleInlineLocation, {encoding: 'utf8'});
+    expect(bundle).toContain('//# sourceMappingURL=data:application/json;base64');
+  });
+
+  it('has no sourcemap comment when set to \'external\'', () => {
+    const bundle = readFileSync(bundleExternalLocation, {encoding: 'utf8'});
+    expect(bundle).not.toContain('//# sourceMappingURL=');
+  });
+
+  it('creates an external sourcemap when set to \'external\'', () => {
+    const sourcemap = readFileSync(bundleExternalSourcemapLocation, {encoding: 'utf8'});
+    expect(sourcemap).toContain(
+        '"sources": ["../../../../../../../packages/esbuild/test/sourcemap/main.ts"]');
+  });
+
+  it('inlines the sourcemap when set to \'both\'', () => {
+    const bundle = readFileSync(bundleInlineLocation, {encoding: 'utf8'});
+    expect(bundle).toContain('//# sourceMappingURL=data:application/json;base64');
+  });
+
+  it('creates an external sourcemap when set to \'both\'', () => {
+    const sourcemap = readFileSync(bundleDefaultSourcemapLocation, {encoding: 'utf8'});
+    expect(sourcemap).toContain(
+        '"sources": ["../../../../../../../packages/esbuild/test/sourcemap/main.ts"]');
+  });
+})

packages/esbuild/test/sourcemap/main.ts

@@ -0,0 +1,8 @@
+export interface Foo {
+  x: number, y: string,
+}
+
+export const foo: Foo = {
+  x: 123,
+  y: 'hello',
+}