fix(es/typescript): Analyze import chain (#9369)

- Closes #9368

---------

Co-authored-by: Donny/강동윤 <kdy1997.dev@gmail.com>

Author: magic-akari

.changeset/wicked-lizards-smoke.md

@@ -0,0 +1,5 @@
+---
+swc_ecma_transforms_typescript: patch
+---
+
+fix(es/typescript): Analyze import chain

crates/swc/tests/tsc-references/amdImportNotAsPrimaryExpression.1.normal.js

@@ -38,9 +38,8 @@ define([
 //// [foo_1.ts]
 define([
     "require",
-    "exports",
-    "./foo_0"
-], function(require, exports, _foo_0) {
+    "exports"
+], function(require, exports) {
     "use strict";
     Object.defineProperty(exports, "__esModule", {
         value: true

crates/swc/tests/tsc-references/amdImportNotAsPrimaryExpression.2.minified.js

@@ -27,9 +27,8 @@ define([
 //// [foo_1.ts]
 define([
     "require",
-    "exports",
-    "./foo_0"
-], function(require, exports, _foo_0) {
+    "exports"
+], function(require, exports) {
     Object.defineProperty(exports, "__esModule", {
         value: !0
     });

crates/swc/tests/tsc-references/commonJSImportNotAsPrimaryExpression.1.normal.js

@@ -35,7 +35,6 @@ var E1;
 Object.defineProperty(exports, "__esModule", {
     value: true
 });
-var foo = require("./foo_0");
 var i;
 var x = {};
 var y = false;

crates/swc/tests/tsc-references/commonJSImportNotAsPrimaryExpression.2.minified.js

@@ -21,4 +21,4 @@ C1.s1 = !0, (E1 = E11 || (E11 = {}))[E1.A = 0] = "A", E1[E1.B = 1] = "B", E1[E1.
 //// [foo_1.ts]
 Object.defineProperty(exports, "__esModule", {
     value: !0
-}), require("./foo_0");
+});

crates/swc/tests/tsc-references/importStatementsInterfaces.1.normal.js

@@ -2,7 +2,6 @@
 var C;
 // no code gen expected
 (function(C) {
-    var a = A;
     var m;
     var p;
     var p = {

crates/swc/tests/tsc-references/importStatementsInterfaces.2.minified.js

@@ -1,5 +1,5 @@
 //// [importStatementsInterfaces.ts]
 var C, D, E;
-C || (C = {}), A, D || (D = {}), (E || (E = {})).xDist = function(x) {
+C || (C = {}), D || (D = {}), (E || (E = {})).xDist = function(x) {
     return 0 - x.x;
 };

crates/swc_ecma_transforms_typescript/src/strip_import_export.rs

@@ -1,6 +1,6 @@
 use std::mem;
 
-use swc_common::collections::AHashSet;
+use swc_common::collections::{AHashMap, AHashSet};
 use swc_ecma_ast::*;
 use swc_ecma_utils::stack_size::maybe_grow_default;
 use swc_ecma_visit::{noop_visit_type, Visit, VisitMut, VisitMutWith, VisitWith};
@@ -10,11 +10,15 @@ use crate::{strip_type::IsConcrete, ImportsNotUsedAsValues};
 #[derive(Debug, Default)]
 struct UsageCollect {
     id_usage: AHashSet<Id>,
+    import_chain: AHashMap<Id, Id>,
 }
 
 impl From<AHashSet<Id>> for UsageCollect {
     fn from(id_usage: AHashSet<Id>) -> Self {
-        Self { id_usage }
+        Self {
+            id_usage,
+            import_chain: Default::default(),
+        }
     }
 }
 
@@ -68,7 +72,15 @@ impl Visit for UsageCollect {
             return;
         };
 
-        get_module_ident(ts_entity_name).visit_with(self);
+        let id = get_module_ident(ts_entity_name);
+
+        if n.is_export {
+            id.visit_with(self);
+            n.id.visit_with(self);
+            return;
+        }
+
+        self.import_chain.insert(n.id.to_id(), id.to_id());
     }
 
     fn visit_export_named_specifier(&mut self, n: &ExportNamedSpecifier) {
@@ -101,6 +113,26 @@ impl UsageCollect {
     fn has_usage(&self, id: &Id) -> bool {
         self.id_usage.contains(id)
     }
+
+    fn analyze_import_chain(&mut self) {
+        if self.import_chain.is_empty() {
+            return;
+        }
+
+        let mut new_usage = AHashSet::default();
+        for id in &self.id_usage {
+            let mut entry = self.import_chain.remove_entry(id);
+            while let Some((id, next)) = entry {
+                new_usage.insert(next);
+                entry = self.import_chain.remove_entry(&id);
+            }
+            if self.import_chain.is_empty() {
+                break;
+            }
+        }
+        self.import_chain.clear();
+        self.id_usage.extend(new_usage);
+    }
 }
 
 fn get_module_ident(ts_entity_name: &TsEntityName) -> &Ident {
@@ -264,6 +296,8 @@ impl VisitMut for StripImportExport {
         n.visit_with(&mut usage_info);
         n.visit_with(&mut declare_info);
 
+        usage_info.analyze_import_chain();
+
         let mut strip_ts_import_equals = StripTsImportEquals;
 
         n.retain_mut(|module_item| match module_item {

crates/swc_ecma_transforms_typescript/tests/__swc_snapshots__/tests/strip.rs/deno_12395_import_equals_2.js

@@ -1,2 +1 @@
-import * as mongo from 'https://deno.land/x/mongo@v0.27.0/mod.ts';
 const mongoClient = {};

crates/swc_ecma_transforms_typescript/tests/fixture/issue-9368/input.ts

@@ -0,0 +1,16 @@
+import { Schemas } from './types.d';
+import AddressResource = Schemas.AddressResource;
+
+// type usage
+const x: AddressResource = {};
+
+
+import { foo, bar } from "mod";
+
+// value usage
+import y = foo.y;
+
+// type usage
+import z = bar.z;
+
+console.log(y as z);

crates/swc_ecma_transforms_typescript/tests/fixture/issue-9368/output.js

@@ -0,0 +1,6 @@
+// type usage
+const x = {};
+import { foo } from "mod";
+// value usage
+const y = foo.y;
+console.log(y);