feat(es/minifier): Respect inline level and preserve native names (#8205

)

**Description:**

Note: Preserving native names is a hack, but it's used by `terser` and it's the only way to preserve the name of `class AbortSignal` while mangling without `keep_classnames: true`. We can special case `AbortSignal`, but let's just follow `terser`.


**Related issue:**

 - vercel/next.js#57904

crates/swc_ecma_lints/src/lib.rs

@@ -1,5 +1,6 @@
 #![cfg_attr(feature = "non_critical_lints", deny(unused))]
 #![cfg_attr(feature = "non_critical_lints", deny(clippy::all))]
+#![allow(rustc::untranslatable_diagnostic_trivial)]
 
 pub mod config;
 pub mod rule;

crates/swc_ecma_minifier/src/compress/optimize/inline.rs

@@ -212,6 +212,12 @@ impl Optimizer<'_> {
                                 }
                             }
 
+                            if u.declared_as_fn_expr {
+                                if self.options.inline != 3 {
+                                    return;
+                                }
+                            }
+
                             should_inline
                         } else {
                             false
@@ -428,6 +434,11 @@ impl Optimizer<'_> {
                                     return;
                                 }
                             }
+                            if init_usage.declared_as_fn_expr {
+                                if self.options.inline != 3 {
+                                    return;
+                                }
+                            }
                         }
                     }
 
@@ -712,10 +723,11 @@ impl Optimizer<'_> {
                 #[allow(unused)]
                 match &decl {
                     Decl::Class(c) => {
-                        if self.options.keep_classnames
+                        if self.options.inline != 3
+                            || self.options.keep_classnames
                             || self.mangle_options.map_or(false, |v| v.keep_class_names)
                         {
-                            log_abort!("inline: [x] Keep fn names");
+                            log_abort!("inline: [x] Keep class names");
                             return;
                         }
 

crates/swc_ecma_minifier/tests/TODO.txt

@@ -332,7 +332,6 @@ reduce_vars/issue_294/input.js
 reduce_vars/issue_3140_4/input.js
 reduce_vars/modified/input.js
 reduce_vars/obj_arg_2/input.js
-reduce_vars/obj_for_1/input.js
 reduce_vars/obj_var_2/input.js
 reduce_vars/passes/input.js
 reduce_vars/perf_3/input.js

crates/swc_ecma_minifier/tests/fixture/next/33458/static/chunks/pages/spread-be872e60d968a0f7/output.js

@@ -41,28 +41,24 @@
                     return PageWithSpread;
                 }
             });
-            var jsx_runtime = __webpack_require__(5893), react = __webpack_require__(7294), Form = __webpack_require__(2726);
-            function _defineProperty(obj, key, value) {
-                return key in obj ? Object.defineProperty(obj, key, {
-                    value: value,
-                    enumerable: !0,
-                    configurable: !0,
-                    writable: !0
-                }) : obj[key] = value, obj;
-            }
-            function _objectSpread(target) {
-                for(var i = 1; i < arguments.length; i++){
-                    var source = null != arguments[i] ? arguments[i] : {}, ownKeys = Object.keys(source);
-                    "function" == typeof Object.getOwnPropertySymbols && (ownKeys = ownKeys.concat(Object.getOwnPropertySymbols(source).filter(function(sym) {
-                        return Object.getOwnPropertyDescriptor(source, sym).enumerable;
-                    }))), ownKeys.forEach(function(key) {
-                        _defineProperty(target, key, source[key]);
-                    });
-                }
-                return target;
-            }
-            var components_Container = function(props) {
-                return (0, jsx_runtime.jsx)(Form.Z, _objectSpread({}, props));
+            var jsx_runtime = __webpack_require__(5893), react = __webpack_require__(7294), Form = __webpack_require__(2726), components_Container = function(props) {
+                return (0, jsx_runtime.jsx)(Form.Z, function(target) {
+                    for(var i = 1; i < arguments.length; i++){
+                        var source = null != arguments[i] ? arguments[i] : {}, ownKeys = Object.keys(source);
+                        "function" == typeof Object.getOwnPropertySymbols && (ownKeys = ownKeys.concat(Object.getOwnPropertySymbols(source).filter(function(sym) {
+                            return Object.getOwnPropertyDescriptor(source, sym).enumerable;
+                        }))), ownKeys.forEach(function(key) {
+                            var value;
+                            value = source[key], key in target ? Object.defineProperty(target, key, {
+                                value: value,
+                                enumerable: !0,
+                                configurable: !0,
+                                writable: !0
+                            }) : target[key] = value;
+                        });
+                    }
+                    return target;
+                }({}, props));
             };
             function PageWithSpread() {
                 var ref = (0, react.useState)(""), text = ref[0], setText = ref[1], handleChange = (0, react.useCallback)(function(e) {

crates/swc_ecma_minifier/tests/fixture/next/36127/2/1/output.js

@@ -1,6 +1,5 @@
 export function regexCheck(regex) {
-    return check;
-    function check(code) {
+    return function(code) {
         return null !== code && regex.test(String.fromCharCode(code));
-    }
+    };
 }

crates/swc_ecma_minifier/tests/fixture/next/36127/2/2/output.js

@@ -1,7 +1,6 @@
 function regexCheck(regex) {
-    return check;
-    function check(code) {
+    return function(code) {
         return null !== code && regex.test(String.fromCharCode(code));
-    }
+    };
 }
 console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo"));

crates/swc_ecma_minifier/tests/fixture/next/36127/2/3/output.js

@@ -22,17 +22,17 @@ export class Text {
     eq(t) {
         if (t == this) return !0;
         if (t.length != this.length || t.lines != this.lines) return !1;
-        let e = this.scanIdentical(t, 1), n = this.length - this.scanIdentical(t, -1), i = new s(this), h = new s(t);
-        for(let t = e, s = e;;){
-            if (i.next(t), h.next(t), t = 0, i.lineBreak != h.lineBreak || i.done != h.done || i.value != h.value) return !1;
-            if (s += i.value.length, i.done || s >= n) return !0;
+        let e = this.scanIdentical(t, 1), n = this.length - this.scanIdentical(t, -1), s = new i(this), h = new i(t);
+        for(let t = e, i = e;;){
+            if (s.next(t), h.next(t), t = 0, s.lineBreak != h.lineBreak || s.done != h.done || s.value != h.value) return !1;
+            if (i += s.value.length, s.done || i >= n) return !0;
         }
     }
     iter(t = 1) {
-        return new s(this, t);
+        return new i(this, t);
     }
     iterRange(t, e = this.length) {
-        return new h(this, t, e);
+        return new s(this, t, e);
     }
     iterLines(t, e) {
         let n;
@@ -42,7 +42,7 @@ export class Text {
             let i = this.line(t).from;
             n = this.iterRange(i, Math.max(i, e == this.lines + 1 ? this.length : e <= 1 ? 0 : this.line(e - 1).to));
         }
-        return new l(n);
+        return new h(n);
     }
     toString() {
         return this.sliceString(0);
@@ -57,7 +57,11 @@ export class Text {
     }
 }
 class t extends Text {
-    constructor(t, e = n(t)){
+    constructor(t, e = function(t) {
+        let e = -1;
+        for (let n of t)e += n.length + 1;
+        return e;
+    }(t)){
         super(), this.text = t, this.length = e;
     }
     get lines() {
@@ -73,24 +77,24 @@ class t extends Text {
             i = l + 1, n++;
         }
     }
-    decompose(e, n, s, h) {
-        let l = e <= 0 && n >= this.length ? this : new t(i(this.text, [
+    decompose(e, i, s, h) {
+        let l = e <= 0 && i >= this.length ? this : new t(n(this.text, [
             ""
-        ], e, n), Math.min(n, this.length) - Math.max(0, e));
+        ], e, i), Math.min(i, this.length) - Math.max(0, e));
         if (1 & h) {
-            let e = s.pop(), n = i(l.text, e.text.slice(), 0, l.length);
-            if (n.length <= 32) s.push(new t(n, e.length + l.length));
+            let e = s.pop(), i = n(l.text, e.text.slice(), 0, l.length);
+            if (i.length <= 32) s.push(new t(i, e.length + l.length));
             else {
-                let e = n.length >> 1;
-                s.push(new t(n.slice(0, e)), new t(n.slice(e)));
+                let e = i.length >> 1;
+                s.push(new t(i.slice(0, e)), new t(i.slice(e)));
             }
         } else s.push(l);
     }
-    replace(n, s, h) {
-        if (!(h instanceof t)) return super.replace(n, s, h);
-        let l = i(this.text, i(h.text, i(this.text, [
+    replace(i, s, h) {
+        if (!(h instanceof t)) return super.replace(i, s, h);
+        let l = n(this.text, n(h.text, n(this.text, [
             ""
-        ], 0, n)), s), r = this.length + h.length - (s - n);
+        ], 0, i)), s), r = this.length + h.length - (s - i);
         return l.length <= 32 ? new t(l, r) : e.from(t.split(l, []), r);
     }
     sliceString(t, e = this.length, n = "\n") {
@@ -189,24 +193,18 @@ class e extends Text {
             return new t(e, i);
         }
         let h = Math.max(32, s >> 5), l = h << 1, r = h >> 1, o = [], f = 0, c = -1, u = [];
-        function a(n) {
-            let i;
-            if (n.lines > l && n instanceof e) for (let t of n.children)a(t);
-            else n.lines > r && (f > r || !f) ? (g(), o.push(n)) : n instanceof t && f && (i = u[u.length - 1]) instanceof t && n.lines + i.lines <= 32 ? (f += n.lines, c += n.length + 1, u[u.length - 1] = new t(i.text.concat(n.text), i.length + 1 + n.length)) : (f + n.lines > h && g(), f += n.lines, c += n.length + 1, u.push(n));
-        }
-        function g() {
+        function a() {
             0 != f && (o.push(1 == u.length ? u[0] : e.from(u, c)), c = -1, f = u.length = 0);
         }
-        for (let t of n)a(t);
-        return g(), 1 == o.length ? o[0] : new e(o, i);
+        for (let i of n)!function n(i) {
+            let s;
+            if (i.lines > l && i instanceof e) for (let t of i.children)n(t);
+            else i.lines > r && (f > r || !f) ? (a(), o.push(i)) : i instanceof t && f && (s = u[u.length - 1]) instanceof t && i.lines + s.lines <= 32 ? (f += i.lines, c += i.length + 1, u[u.length - 1] = new t(s.text.concat(i.text), s.length + 1 + i.length)) : (f + i.lines > h && a(), f += i.lines, c += i.length + 1, u.push(i));
+        }(i);
+        return a(), 1 == o.length ? o[0] : new e(o, i);
     }
 }
-function n(t) {
-    let e = -1;
-    for (let n of t)e += n.length + 1;
-    return e;
-}
-function i(t, e, n = 0, i = 1e9) {
+function n(t, e, n = 0, i = 1e9) {
     for(let s = 0, h = 0, l = !0; h < t.length && s <= i; h++){
         let r = t[h], o = s + r.length;
         o >= n && (o > i && (r = r.slice(0, i - s)), s < n && (r = r.slice(n - s)), l ? (e[e.length - 1] += r, l = !1) : e.push(r)), s = o + 1;
@@ -216,7 +214,7 @@ function i(t, e, n = 0, i = 1e9) {
 Text.empty = new t([
     ""
 ], 0);
-class s {
+class i {
     constructor(e, n = 1){
         this.dir = n, this.done = !1, this.lineBreak = !1, this.value = "", this.nodes = [
             e
@@ -247,9 +245,9 @@ class s {
         return t < 0 && (this.nextInner(-t, -this.dir), t = this.value.length), this.nextInner(t, this.dir);
     }
 }
-class h {
+class s {
     constructor(t, e, n){
-        this.value = "", this.done = !1, this.cursor = new s(t, e > n ? -1 : 1), this.pos = e > n ? t.length : 0, this.from = Math.min(e, n), this.to = Math.max(e, n);
+        this.value = "", this.done = !1, this.cursor = new i(t, e > n ? -1 : 1), this.pos = e > n ? t.length : 0, this.from = Math.min(e, n), this.to = Math.max(e, n);
     }
     nextInner(t, e) {
         if (e < 0 ? this.pos <= this.from : this.pos >= this.to) return this.value = "", this.done = !0, this;
@@ -266,7 +264,7 @@ class h {
         return this.cursor.lineBreak && "" != this.value;
     }
 }
-class l {
+class h {
     constructor(t){
         this.inner = t, this.afterBreak = !0, this.value = "", this.done = !1;
     }
@@ -280,7 +278,7 @@ class l {
 }
 "undefined" != typeof Symbol && (Text.prototype[Symbol.iterator] = function() {
     return this.iter();
-}, s.prototype[Symbol.iterator] = h.prototype[Symbol.iterator] = l.prototype[Symbol.iterator] = function() {
+}, i.prototype[Symbol.iterator] = s.prototype[Symbol.iterator] = h.prototype[Symbol.iterator] = function() {
     return this;
 });
 export class Line {