From 03d8a3a0ddb843ded43134265973557dd48e14a7 Mon Sep 17 00:00:00 2001
From: Alexander Akait <4567934+alexander-akait@users.noreply.github.com>
Date: Wed, 22 Jun 2022 08:54:25 +0300
Subject: [PATCH] feat(html/minifier): Add `remove_redundant_attributes`
 (#5023)

---
 crates/swc_html_minifier/src/lib.rs           | 35 +++++++++++--------
 crates/swc_html_minifier/src/option.rs        |  2 ++
 .../config.json                               |  3 ++
 .../input.html                                | 15 ++++++++
 .../output.min.html                           |  3 ++
 5 files changed, 43 insertions(+), 15 deletions(-)
 create mode 100644 crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/config.json
 create mode 100644 crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/input.html
 create mode 100644 crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/output.min.html

diff --git a/crates/swc_html_minifier/src/lib.rs b/crates/swc_html_minifier/src/lib.rs
index 386e0e1ac19..b3639ffab78 100644
--- a/crates/swc_html_minifier/src/lib.rs
+++ b/crates/swc_html_minifier/src/lib.rs
@@ -278,6 +278,7 @@ struct Minifier {
     collapse_whitespaces: Option<CollapseWhitespaces>,
 
     remove_empty_attributes: bool,
+    remove_redundant_attributes: bool,
     collapse_boolean_attributes: bool,
     minify_json: bool,
     minify_js: bool,
@@ -909,6 +910,7 @@ impl Minifier {
                 force_set_html5_doctype: self.force_set_html5_doctype,
                 collapse_whitespaces: self.collapse_whitespaces.clone(),
                 remove_empty_attributes: self.remove_empty_attributes,
+                remove_redundant_attributes: self.remove_empty_attributes,
                 collapse_boolean_attributes: self.collapse_boolean_attributes,
                 minify_js: self.minify_js,
                 minify_json: self.minify_json,
@@ -1005,23 +1007,25 @@ impl VisitMut for Minifier {
                 return true;
             }
 
-            if self.is_default_attribute_value(
-                n.namespace,
-                &n.tag_name,
-                &attribute.name,
-                match &*n.tag_name {
-                    "script" if matches!(n.namespace, Namespace::HTML | Namespace::SVG) => {
-                        let original_value = attribute.value.as_ref().unwrap();
+            if self.remove_redundant_attributes
+                && self.is_default_attribute_value(
+                    n.namespace,
+                    &n.tag_name,
+                    &attribute.name,
+                    match &*n.tag_name {
+                        "script" if matches!(n.namespace, Namespace::HTML | Namespace::SVG) => {
+                            let original_value = attribute.value.as_ref().unwrap();
 
-                        if let Some(next) = original_value.split(';').next() {
-                            next
-                        } else {
-                            original_value
+                            if let Some(next) = original_value.split(';').next() {
+                                next
+                            } else {
+                                original_value
+                            }
                         }
-                    }
-                    _ => attribute.value.as_ref().unwrap(),
-                },
-            ) {
+                        _ => attribute.value.as_ref().unwrap(),
+                    },
+                )
+            {
                 return false;
             }
 
@@ -1321,6 +1325,7 @@ fn create_minifier(context_element: Option<&Element>, options: &MinifyOptions) -
         collapse_whitespaces: options.collapse_whitespaces.clone(),
 
         remove_empty_attributes: options.remove_empty_attributes,
+        remove_redundant_attributes: options.remove_redundant_attributes,
         collapse_boolean_attributes: options.collapse_boolean_attributes,
 
         minify_js: options.minify_js,
diff --git a/crates/swc_html_minifier/src/option.rs b/crates/swc_html_minifier/src/option.rs
index 50800a6f78a..1158e70a251 100644
--- a/crates/swc_html_minifier/src/option.rs
+++ b/crates/swc_html_minifier/src/option.rs
@@ -18,6 +18,8 @@ pub struct MinifyOptions {
     #[serde(default = "true_by_default")]
     pub remove_empty_attributes: bool,
     #[serde(default = "true_by_default")]
+    pub remove_redundant_attributes: bool,
+    #[serde(default = "true_by_default")]
     pub collapse_boolean_attributes: bool,
     #[serde(default = "true_by_default")]
     pub minify_js: bool,
diff --git a/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/config.json b/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/config.json
new file mode 100644
index 00000000000..fd42b4a55ac
--- /dev/null
+++ b/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/config.json
@@ -0,0 +1,3 @@
+{
+  "removeRedundantAttributes": false
+}
\ No newline at end of file
diff --git a/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/input.html b/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/input.html
new file mode 100644
index 00000000000..4a045e0a326
--- /dev/null
+++ b/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/input.html
@@ -0,0 +1,15 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <title>Document</title>
+    <link rel="stylesheet" href="a.css">
+    <link rel="stylesheet" href="b.css" type="text/css">
+    <link rel="stylesheet" href="b.css" type="TEXT/CSS">
+    <link rel="stylesheet" href="c.css" type="   text/css   ">
+    <link rel="stylesheet" href="d.css" type="">
+    <link rel="stylesheet" href="d.css" type="unknown/unknown">
+</head>
+<body>
+<div>test</div>
+</body>
+</html>
\ No newline at end of file
diff --git a/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/output.min.html b/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/output.min.html
new file mode 100644
index 00000000000..e39c53fcdf3
--- /dev/null
+++ b/crates/swc_html_minifier/tests/fixture/attribute/disabled-remove_redundant_attributes/output.min.html
@@ -0,0 +1,3 @@
+<!doctype html><html lang=en><title>Document</title><link rel=stylesheet href=a.css><link rel=stylesheet href=b.css type=text/css><link rel=stylesheet href=b.css type=TEXT/CSS><link rel=stylesheet href=c.css type="   text/css   "><link rel=stylesheet href=d.css type=""><link rel=stylesheet href=d.css type=unknown/unknown><body>
+<div>test</div>
+