Fix regression where main was ignored on browser object packages (#528)

* fix regression where main was ignored on browser object packages

* fix test output

* fix test output

src/commands/install.ts

@@ -178,8 +178,7 @@ function resolveWebDependency(dep: string): DependencyLoc {
     depManifest['browser:module'] ||
     depManifest.module ||
     depManifest['main:esnext'] ||
-    depManifest.browser ||
-    depManifest.main;
+    depManifest.browser;
   // Some packages define "browser" as an object. We'll do our best to find the
   // right entrypoint in an entrypoint object, or fail otherwise.
   // See: https://github.com/defunctzombie/package-browser-field-spec
@@ -191,6 +190,10 @@ function resolveWebDependency(dep: string): DependencyLoc {
       foundEntrypoint['./'] ||
       foundEntrypoint['.'];
   }
+  // If browser object is set but no relevant entrypoint is found, fall back to "main".
+  if (!foundEntrypoint) {
+    foundEntrypoint = depManifest.main;
+  }
   // Sometimes packages don't give an entrypoint, assuming you'll fall back to "index.js".
   const isImplicitEntrypoint = !foundEntrypoint;
   if (isImplicitEntrypoint) {

test/integration/dep-browser-entrypoint-object/expected-install/import-map.json

@@ -1,5 +1,6 @@
 {
   "imports": {
-    "mock-test-package": "./mock-test-package.js"
+    "package-has-valid": "./package-has-valid.js",
+    "package-no-valid": "./package-no-valid.js"
   }
 }

test/integration/dep-browser-entrypoint-object/expected-install/package-no-valid.js

@@ -0,0 +1,3 @@
+const foobar = 42;
+
+export { foobar };

test/integration/dep-browser-entrypoint-object/expected-output.txt

@@ -1,4 +1,5 @@
 - snowpack installing...
 ✔ snowpack install complete.
   ⦿ web_modules/             size       gzip       brotli
-    └─ mock-test-package.js    XXXX KB    XXXX KB    XXXX KB
+    ├─ package-has-valid.js    XXXX KB    XXXX KB    XXXX KB
+    └─ package-no-valid.js    XXXX KB    XXXX KB    XXXX KB

test/integration/dep-browser-entrypoint-object/package.json

@@ -1,12 +1,13 @@
 {
-  "description": "Test that we can handle a package.json 'browser' object entrypoint",
+  "description": "Test that we properly handle a package.json 'browser' object.",
   "scripts": {
     "TEST": "node ../../../pkg/dist-node/index.bin.js"
   },
   "snowpack": {
-    "install": ["mock-test-package"]
+    "install": ["package-has-valid", "package-no-valid"]
   },
   "dependencies": {
-    "mock-test-package": "^1.2.3"
+    "package-has-valid": "^1.2.3",
+    "package-no-valid": "^1.2.3"
   }
 }