feat(mangler): use characters in the order of their likely frequency

crates/oxc_mangler/src/lib.rs

@@ -424,8 +424,32 @@ fn is_keyword(s: &str) -> bool {
 #[repr(C, align(64))]
 struct Aligned64([u8; 64]);
 
+/// The characters are in frequency order, so that the characters with higher frequency are used first.
+///
+/// This idea was inspired by nanoid. <https://github.com/ai/nanoid/blob/5.0.9/url-alphabet/index.js>
+///
+/// This list was generated by the following steps:
+/// 1. Generate a source code with replacing all manglable variable names with `$` (assuming `$` is the least used character).
+///    You can do this by passing the following `blank` function to the `generate_name` parameter of [Mangler::build_with_symbols_and_scopes_impl].
+///    ```rust
+///    fn blank(_: usize) -> InlineString<12> {
+///        let mut str = InlineString::new();
+///        unsafe { str.push_unchecked(b"$"[0]); }
+///        str
+///    }
+///    ```
+/// 2. Run the following command in `target/minifier/default` to check generate the list:
+///    ```
+///    find . -type f -exec cat {} + | `# concat all files in that directory` \
+///      tr -d '\n' | fold -w1 | `# separate each characters in to each line` \
+///      grep -E '[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_0123456789]' | `# filter the character` \
+///      sort | uniq -c | `# count each characters` \
+///      sort -nr | awk '{print $2}' | tr -d '\n' `# format output`
+///    ```
+///    The result I got is `etnriaoscludfpmhg_10vy2436b8x579SCwTEDOkAjMNPFILRzBVHUWGKqJYXZQ`.
+/// 3. Add `$` at the end and then move all numbers to the end of the list.
 const BASE54_CHARS: Aligned64 =
-    Aligned64(*b"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_0123456789");
+    Aligned64(*b"etnriaoscludfpmhg_vybxSCwTEDOkAjMNPFILRzBVHUWGKqJYXZQ$1024368579");
 
 /// Get the shortest mangled name for a given n.
 /// Code adapted from [terser](https://github.com/terser/terser/blob/8b966d687395ab493d2c6286cc9dd38650324c11/lib/scope.js#L1041-L1051)

tasks/minsize/minsize.snap

@@ -1,27 +1,27 @@
            | Oxc        | ESBuild    | Oxc        | ESBuild    |
 Original   | minified   | minified   | gzip       | gzip       | Fixture
 -------------------------------------------------------------------------------------
-72.14 kB   | 23.57 kB   | 23.70 kB   | 8.55 kB    | 8.54 kB    | react.development.js
+72.14 kB   | 23.57 kB   | 23.70 kB   | 8.52 kB    | 8.54 kB    | react.development.js
 
-173.90 kB  | 59.68 kB   | 59.82 kB   | 19.25 kB   | 19.33 kB   | moment.js 
+173.90 kB  | 59.68 kB   | 59.82 kB   | 19.20 kB   | 19.33 kB   | moment.js 
 
-287.63 kB  | 89.52 kB   | 90.07 kB   | 31.07 kB   | 31.95 kB   | jquery.js 
+287.63 kB  | 89.52 kB   | 90.07 kB   | 30.95 kB   | 31.95 kB   | jquery.js 
 
-342.15 kB  | 117.69 kB  | 118.14 kB  | 43.66 kB   | 44.37 kB   | vue.js    
+342.15 kB  | 117.69 kB  | 118.14 kB  | 43.55 kB   | 44.37 kB   | vue.js    
 
-544.10 kB  | 71.49 kB   | 72.48 kB   | 25.92 kB   | 26.20 kB   | lodash.js 
+544.10 kB  | 71.49 kB   | 72.48 kB   | 25.89 kB   | 26.20 kB   | lodash.js 
 
-555.77 kB  | 271.48 kB  | 270.13 kB  | 88.45 kB   | 90.80 kB   | d3.js     
+555.77 kB  | 271.48 kB  | 270.13 kB  | 88.38 kB   | 90.80 kB   | d3.js     
 
-1.01 MB    | 457.63 kB  | 458.89 kB  | 123.79 kB  | 126.71 kB  | bundle.min.js
+1.01 MB    | 457.63 kB  | 458.89 kB  | 123.53 kB  | 126.71 kB  | bundle.min.js
 
-1.25 MB    | 650.59 kB  | 646.76 kB  | 161.49 kB  | 163.73 kB  | three.js  
+1.25 MB    | 650.59 kB  | 646.76 kB  | 161.11 kB  | 163.73 kB  | three.js  
 
-2.14 MB    | 718.83 kB  | 724.14 kB  | 162.40 kB  | 181.07 kB  | victory.js
+2.14 MB    | 718.83 kB  | 724.14 kB  | 162.15 kB  | 181.07 kB  | victory.js
 
-3.20 MB    | 1.01 MB    | 1.01 MB    | 325.18 kB  | 331.56 kB  | echarts.js
+3.20 MB    | 1.01 MB    | 1.01 MB    | 324.36 kB  | 331.56 kB  | echarts.js
 
-6.69 MB    | 2.30 MB    | 2.31 MB    | 469.99 kB  | 488.28 kB  | antd.js   
+6.69 MB    | 2.30 MB    | 2.31 MB    | 469.42 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.37 MB    | 3.49 MB    | 866.64 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.37 MB    | 3.49 MB    | 864.74 kB  | 915.50 kB  | typescript.js