diff --git a/bench/.gitignore b/bench/.gitignore
index e9dc357..bafe521 100644
--- a/bench/.gitignore
+++ b/bench/.gitignore
@@ -1,2 +1,4 @@
 node_modules/
 min/
+hyperbuild-bench/Cargo.lock
+hyperbuild-bench/target/
diff --git a/bench/bench.js b/bench/bench.js
index a59d7e9..beb0c3a 100644
--- a/bench/bench.js
+++ b/bench/bench.js
@@ -1,65 +1,39 @@
-"use strict";
-
 const benchmark = require('benchmark');
-const chartjs = require('chartjs-node');
+const childProcess = require('child_process');
 const fs = require('fs');
 const path = require('path');
 const programs = require('./minifiers');
 const tests = require('./tests');
 
-const colours = [
-  {
-    backgroundColor: '#9ad0f5',
-    borderColor: '#47aaec',
-  },
-  {
-    backgroundColor: '#ffb0c1',
-    borderColor: '#ff87a1',
-  },
-  {
-    backgroundColor: '#a4dfdf',
-    borderColor: '#4bc0c0',
-  },
-];
-const chartOptions = (title, displayLegend, yTick = t => t) => ({
-  options: {
-    title: {
-      display: true,
-      text: title,
-    },
-    scales: {
-      xAxes: [{
-        barPercentage: 0.5,
-        gridLines: {
-          color: '#ccc',
-        },
-        ticks: {
-          fontColor: '#222',
-        },
-      }],
-      yAxes: [{
-        gridLines: {
-          color: '#666',
-        },
-        ticks: {
-          callback: yTick,
-          fontColor: '#222',
-        },
-      }],
-    },
-    legend: {
-      display: displayLegend,
-      labels: {
-        fontFamily: 'Ubuntu, sans-serif',
-        fontColor: '#000',
-      },
-    },
-  },
-});
-const renderChart = async (file, cfg) => {
-  const chart = new chartjs(435, 320);
-  await chart.drawChart(cfg);
-  await chart.writeImageToFile('image/png', path.join(__dirname, `${file}.png`));
+const cmd = (command, ...args) => {
+  const throwErr = msg => {
+    throw new Error(`${msg}\n  ${command} ${args.join(' ')}`);
+  };
+
+  const {status, signal, error, stdout, stderr} = childProcess.spawnSync(command, args.map(String), {
+    stdio: ['ignore', 'pipe', 'pipe'],
+    encoding: 'utf8',
+  });
+  if (error) {
+    throwErr(error.message);
+  }
+  if (signal) {
+    throwErr(`Command exited with signal ${signal}`);
+  }
+  if (status !== 0) {
+    throwErr(`Command exited with status ${status}`);
+  }
+  if (stderr) {
+    throwErr(`stderr: ${stderr}`);
+  }
+  return stdout;
+};
+
+const fromEntries = entries => {
+  if (Object.fromEntries) return Object.fromEntries(entries);
+  const obj = {};
+  for (const [prop, val] of entries) obj[prop] = val;
+  return obj;
 };
 
 const sizes = {};
@@ -91,52 +65,37 @@ for (const t of tests) {
     }
   }
 }
+fs.writeFileSync(path.join(__dirname, 'minification.json'), JSON.stringify(sizes, null, 2));
 
-const suite = new benchmark.Suite();
-for (const p of Object.keys(programs)) {
-  suite.add(p, () => {
-    for (const t of tests) {
-      programs[p](t.content);
-    }
-  });
-}
-suite
-  .on('cycle', event => {
-    console.info(event.target.toString());
-  })
-  .on('complete', async function () {
-    const speedResults = this.map(b => ({
-      name: b.name,
-      ops: b.hz,
-    }));
-    fs.writeFileSync(path.join(__dirname, "speed.json"), JSON.stringify(speedResults, null, 2));
-    await renderChart('speed', {
-      type: 'bar',
-      data: {
-        labels: speedResults.map(r => r.name),
-        datasets: [{
-          ...colours[0],
-          data: speedResults.map(r => r.ops),
-        }],
-      },
-      ...chartOptions('Operations per second (higher is better)', false),
+const runTest = test => new Promise((resolve, reject) => {
+  // Run JS libraries.
+  const suite = new benchmark.Suite();
+  for (const p of Object.keys(programs)) {
+    suite.add(p, () => {
+      programs[p](test.content);
     });
+  }
+  suite
+    .on('cycle', event => console.info(test.name, event.target.toString()))
+    .on('complete', () => resolve(fromEntries(suite.map(b => [b.name, b.hz]))))
+    .on('error', reject)
+    .run({'async': true});
+});
 
-    const testNames = Object.keys(sizes);
-    const programNames = Object.keys(programs);
-    fs.writeFileSync(path.join(__dirname, "minification.json"), JSON.stringify(sizes, null, 2));
-    await renderChart('minification', {
-      type: 'bar',
-      scaleFontColor: 'red',
-      data: {
-        labels: testNames,
-        datasets: programNames.map((program, i) => ({
-          label: program,
-          ...colours[i],
-          data: testNames.map(test => sizes[test][program].relative * 100),
-        })),
-      },
-      ...chartOptions('Relative minified HTML file size (lower is better)', true, tick => `${tick}%`),
-    });
-  })
-  .run({'async': true});
+(async () => {
+  const results = {};
+
+  // Run Rust library.
+  for (const [testName, testOps] of JSON.parse(cmd(
+    path.join(__dirname, 'hyperbuild-bench', 'target', 'release', 'hyperbuild-bench'),
+    '--iterations', 100,
+    '--tests', path.join(__dirname, 'tests'),
+  ))) {
+    results[testName] = {hyperbuild: testOps};
+  }
+
+  for (const t of tests) {
+    Object.assign(results[t.name], await runTest(t));
+  }
+  fs.writeFileSync(path.join(__dirname, 'speed.json'), JSON.stringify(results, null, 2));
+})();
diff --git a/bench/fetch.js b/bench/fetch.js
index e7f711a..0bb1147 100644
--- a/bench/fetch.js
+++ b/bench/fetch.js
@@ -9,6 +9,7 @@ const tests = {
   "Bootstrap": "https://getbootstrap.com/docs/3.4/css/",
   "Bing": "https://www.bing.com/",
   "Coding Horror": "https://blog.codinghorror.com/",
+  "ECMA-262": "https://www.ecma-international.org/ecma-262/10.0/index.html",
   "Google": "https://www.google.com/",
   "Hacker News": "https://news.ycombinator.com/",
   "NY Times": "https://www.nytimes.com/",
diff --git a/bench/graph.js b/bench/graph.js
new file mode 100644
index 0000000..977b2e2
--- /dev/null
+++ b/bench/graph.js
@@ -0,0 +1,86 @@
+const chartjs = require('chartjs-node');
+const fs = require('fs');
+const path = require('path');
+const tests = require('./tests');
+
+const colours = {
+  'hyperbuild': '#041f60',
+  'hyperbuild-nodejs': '#0476d0',
+  'minimize': '#3cacae',
+  'html-minifier': '#5d6c89',
+};
+
+const chartOptions = (title, displayLegend, yTick = t => t) => ({
+  options: {
+    title: {
+      display: true,
+      text: title,
+    },
+    scales: {
+      xAxes: [{
+        barPercentage: 0.75,
+        gridLines: {
+          color: '#ccc',
+        },
+        ticks: {
+          fontColor: '#222',
+        },
+      }],
+      yAxes: [{
+        gridLines: {
+          color: '#666',
+        },
+        ticks: {
+          callback: yTick,
+          fontColor: '#222',
+        },
+      }],
+    },
+    legend: {
+      display: displayLegend,
+      labels: {
+        fontFamily: 'Ubuntu, sans-serif',
+        fontColor: '#000',
+      },
+    },
+  },
+});
+
+const renderChart = async (file, cfg) => {
+  const chart = new chartjs(435, 320);
+  await chart.drawChart(cfg);
+  await chart.writeImageToFile('image/png', path.join(__dirname, `${file}.png`));
+};
+
+(async () => {
+  const testNames = tests.map(t => t.name).sort();
+
+  const speedResults = JSON.parse(fs.readFileSync(path.join(__dirname, 'speed.json'), 'utf8'));
+  await renderChart('speed', {
+    type: 'bar',
+    data: {
+      labels: testNames,
+      datasets: ['hyperbuild', 'hyperbuild-nodejs', 'minimize', 'html-minifier'].map(program => ({
+        label: program,
+        backgroundColor: colours[program],
+        data: testNames.map(test => speedResults[test][program] / speedResults[test]['hyperbuild'] * 100),
+      })),
+    },
+    ...chartOptions('Relative operations per second (higher is better)', true, tick => `${tick}%`),
+  });
+
+  const sizes = JSON.parse(fs.readFileSync(path.join(__dirname, 'minification.json'), 'utf8'));
+  await renderChart('minification', {
+    type: 'bar',
+    scaleFontColor: 'red',
+    data: {
+      labels: testNames,
+      datasets: ['hyperbuild-nodejs', 'html-minifier', 'minimize'].map(program => ({
+        label: program,
+        backgroundColor: colours[program],
+        data: testNames.map(test => sizes[test][program].relative * 100),
+      })),
+    },
+    ...chartOptions('Relative minified HTML file size (lower is better)', true, tick => `${tick}%`),
+  });
+})();
diff --git a/bench/hyperbuild-bench/Cargo.toml b/bench/hyperbuild-bench/Cargo.toml
new file mode 100644
index 0000000..76b466d
--- /dev/null
+++ b/bench/hyperbuild-bench/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "hyperbuild-bench"
+publish = false
+version = "0.0.1"
+authors = ["Wilson Lin <code@wilsonl.in>"]
+edition = "2018"
+
+[dependencies]
+hyperbuild = { path = "../.." }
+structopt = "0.3.5"
+serde = { version = "1.0.104", features = ["derive"] }
+serde_json = "1.0.44"
diff --git a/bench/hyperbuild-bench/src/main.rs b/bench/hyperbuild-bench/src/main.rs
new file mode 100644
index 0000000..a81ba11
--- /dev/null
+++ b/bench/hyperbuild-bench/src/main.rs
@@ -0,0 +1,34 @@
+use hyperbuild::hyperbuild;
+use std::fs;
+use std::io::{stdout};
+use std::time::Instant;
+use structopt::StructOpt;
+
+#[derive(StructOpt)]
+struct Args {
+    #[structopt(long, parse(from_os_str))]
+    tests: std::path::PathBuf,
+    #[structopt(long)]
+    iterations: usize,
+}
+
+fn main() {
+    let args = Args::from_args();
+    let tests = fs::read_dir(args.tests).unwrap().map(|d| d.unwrap());
+
+    let mut results: Vec<(String, f64)> = Vec::new();
+
+    for t in tests {
+        let source = fs::read(t.path()).unwrap();
+        let start = Instant::now();
+        for _ in 0..args.iterations {
+            let mut data = source.to_vec();
+            hyperbuild(&mut data).unwrap();
+        };
+        let elapsed = start.elapsed().as_secs_f64();
+        let ops = args.iterations as f64 / elapsed;
+        results.push((t.file_name().to_str().unwrap().to_string(), ops));
+    };
+
+    serde_json::to_writer(stdout(), &results).unwrap();
+}
diff --git a/bench/install.sh b/bench/install.sh
new file mode 100755
index 0000000..08f8a54
--- /dev/null
+++ b/bench/install.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+set -e
+
+rm -rf node_modules
+HYPERBUILD_NODEJS_SKIP_BIN_DOWNLOAD=1 npm i
+pushd hyperbuild-bench
+cargo build --release
+popd
diff --git a/bench/minification.json b/bench/minification.json
index ce1b201..67cebe6 100644
--- a/bench/minification.json
+++ b/bench/minification.json
@@ -9,8 +9,8 @@
       "relative": 0.6330862904281787
     },
     "html-minifier": {
-      "absolute": 488839,
-      "relative": 0.8534572912574746
+      "absolute": 488822,
+      "relative": 0.8534276111911309
     },
     "minimize": {
       "absolute": 495105,
@@ -45,8 +45,8 @@
       "relative": 0.6222239353466829
     },
     "html-minifier": {
-      "absolute": 137061,
-      "relative": 0.8805095688708154
+      "absolute": 137026,
+      "relative": 0.8802847212853573
     },
     "minimize": {
       "absolute": 137358,
@@ -63,8 +63,8 @@
       "relative": 0.7342292960872684
     },
     "html-minifier": {
-      "absolute": 270621,
-      "relative": 0.7325266961711803
+      "absolute": 270604,
+      "relative": 0.732480679957232
     },
     "minimize": {
       "absolute": 279252,
@@ -99,8 +99,8 @@
       "relative": 0.5906241489629755
     },
     "html-minifier": {
-      "absolute": 383586,
-      "relative": 0.9762867679809012
+      "absolute": 383578,
+      "relative": 0.9762664067212518
     },
     "minimize": {
       "absolute": 384579,
@@ -117,8 +117,8 @@
       "relative": 0.5157900380676639
     },
     "html-minifier": {
-      "absolute": 28464,
-      "relative": 0.5087126695619538
+      "absolute": 28448,
+      "relative": 0.5084267152788948
     },
     "minimize": {
       "absolute": 30643,
@@ -135,8 +135,8 @@
       "relative": 0.6978107321127253
     },
     "html-minifier": {
-      "absolute": 1888047,
-      "relative": 0.9521424184017114
+      "absolute": 1887947,
+      "relative": 0.9520919883849586
     },
     "minimize": {
       "absolute": 1888704,
@@ -153,8 +153,8 @@
       "relative": 0.5387307214917895
     },
     "html-minifier": {
-      "absolute": 1115700,
-      "relative": 0.7231445803045672
+      "absolute": 1115617,
+      "relative": 0.7230907835848708
     },
     "minimize": {
       "absolute": 1117526,
@@ -171,8 +171,8 @@
       "relative": 0.5613076908178878
     },
     "html-minifier": {
-      "absolute": 89329,
-      "relative": 0.5766919089212971
+      "absolute": 89321,
+      "relative": 0.5766402623645085
     },
     "minimize": {
       "absolute": 91363,
@@ -189,8 +189,8 @@
       "relative": 0.9003600363028295
     },
     "html-minifier": {
-      "absolute": 273191,
-      "relative": 0.9082057027356775
+      "absolute": 273174,
+      "relative": 0.9081491873418815
     },
     "minimize": {
       "absolute": 273887,
@@ -207,8 +207,8 @@
       "relative": 0.5520822745589214
     },
     "html-minifier": {
-      "absolute": 1307604,
-      "relative": 0.5359190926945385
+      "absolute": 1307563,
+      "relative": 0.5359022889200009
     },
     "minimize": {
       "absolute": 1368203,
diff --git a/bench/minification.png b/bench/minification.png
index 9a7223d..5f92585 100644
Binary files a/bench/minification.png and b/bench/minification.png differ
diff --git a/bench/minifiers.js b/bench/minifiers.js
index 941ccca..7561f4f 100644
--- a/bench/minifiers.js
+++ b/bench/minifiers.js
@@ -3,39 +3,24 @@ const hyperbuild = require("hyperbuild");
 const minimize = require("minimize");
 
 module.exports = {
-  'hyperbuild-nodejs': content => hyperbuild.minify(Buffer.from(content)),
+  'hyperbuild-nodejs': content => hyperbuild.minify(content),
   'html-minifier': content => htmlMinifier.minify(content, {
-    caseSensitive: false,
     collapseBooleanAttributes: true,
     collapseInlineTagWhitespace: true,
     collapseWhitespace: true,
-    conservativeWhitespace: false,
     customEventAttributes: [],
     decodeEntities: true,
-    html5: true,
     ignoreCustomComments: [],
     ignoreCustomFragments: [/<\?[\s\S]*?\?>/],
-    includeAutoGeneratedTags: true,
-    keepClosingSlash: false,
-    minifyCSS: false,
-    minifyJS: false,
-    minifyURLs: false,
-    preserveLineBreaks: false,
-    preventAttributesEscaping: false,
     processConditionalComments: true,
-    processScripts: [],
     removeAttributeQuotes: true,
     removeComments: true,
-    removeEmptyAttributes: false,
-    removeEmptyElements: false,
+    removeEmptyAttributes: true,
     removeOptionalTags: true,
     removeRedundantAttributes: true,
     removeScriptTypeAttributes: true,
     removeStyleLinkTypeAttributes: true,
     removeTagWhitespace: true,
-    sortAttributes: false,
-    sortClassName: false,
-    trimCustomFragments: false,
     useShortDoctype: true,
   }),
   'minimize': content => new minimize().parse(content),
diff --git a/bench/package.json b/bench/package.json
index 0d10df1..07de493 100644
--- a/bench/package.json
+++ b/bench/package.json
@@ -12,6 +12,9 @@
     "request": "^2.88.0",
     "request-promise-native": "^1.0.8"
   },
+  "engines": {
+    "node": "10.x"
+  },
   "scripts": {
     "start": "node bench.js"
   }
diff --git a/bench/speed.json b/bench/speed.json
index 9937937..a5f26d4 100644
--- a/bench/speed.json
+++ b/bench/speed.json
@@ -1,14 +1,74 @@
-[
-  {
-    "name": "hyperbuild-nodejs",
-    "ops": 10.158435796714862
+{
+  "Amazon.html": {
+    "hyperbuild": 245.46705260338564,
+    "hyperbuild-nodejs": 145.21435374237635,
+    "html-minifier": 16.19830761009811,
+    "minimize": 95.71966364576267
   },
-  {
-    "name": "html-minifier",
-    "ops": 0.9598865156998558
+  "BBC.html": {
+    "hyperbuild": 429.2291873495222,
+    "hyperbuild-nodejs": 251.3721939160052,
+    "html-minifier": 18.333446052847226,
+    "minimize": 108.38902861455512
   },
-  {
-    "name": "minimize",
-    "ops": 3.6888006698975837
+  "Bootstrap.html": {
+    "hyperbuild": 235.08368235051825,
+    "hyperbuild-nodejs": 156.19542771462898,
+    "html-minifier": 8.557266916672539,
+    "minimize": 22.359774537863895
+  },
+  "Bing.html": {
+    "hyperbuild": 1008.1262435363229,
+    "hyperbuild-nodejs": 585.3489088472239,
+    "html-minifier": 79.35385186294975,
+    "minimize": 435.31581246812584
+  },
+  "Coding Horror.html": {
+    "hyperbuild": 1146.867798530376,
+    "hyperbuild-nodejs": 680.2295027510518,
+    "html-minifier": 45.63362214760677,
+    "minimize": 164.51899348138494
+  },
+  "Google.html": {
+    "hyperbuild": 344.0346646025321,
+    "hyperbuild-nodejs": 317.3708534283478,
+    "html-minifier": 29.36827883130167,
+    "minimize": 365.1698468973524
+  },
+  "Hacker News.html": {
+    "hyperbuild": 1804.5683188361834,
+    "hyperbuild-nodejs": 1259.6432378637871,
+    "html-minifier": 66.43984413610241,
+    "minimize": 255.30928557346104
+  },
+  "NY Times.html": {
+    "hyperbuild": 123.84742876588177,
+    "hyperbuild-nodejs": 51.83081525871115,
+    "html-minifier": 7.334756953956464,
+    "minimize": 59.400301132747934
+  },
+  "Reddit.html": {
+    "hyperbuild": 109.45057921629598,
+    "hyperbuild-nodejs": 66.80243904185947,
+    "html-minifier": 6.3323721760167695,
+    "minimize": 44.528247219895
+  },
+  "Stack Overflow.html": {
+    "hyperbuild": 763.6540095978328,
+    "hyperbuild-nodejs": 496.21357271825997,
+    "html-minifier": 39.39722290667494,
+    "minimize": 148.07292819104936
+  },
+  "Twitter.html": {
+    "hyperbuild": 376.9341764747767,
+    "hyperbuild-nodejs": 208.2611701306221,
+    "html-minifier": 42.264558908660206,
+    "minimize": 136.3651156178245
+  },
+  "Wikipedia.html": {
+    "hyperbuild": 52.02792034641937,
+    "hyperbuild-nodejs": 32.045431164840046,
+    "html-minifier": 2.35238631274572,
+    "minimize": 7.878943786969402
   }
-]
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/bench/speed.png b/bench/speed.png
index 0463a3d..80e8dee 100644
Binary files a/bench/speed.png and b/bench/speed.png differ
diff --git a/bench/tests.js b/bench/tests.js
index f39beca..3385756 100644
--- a/bench/tests.js
+++ b/bench/tests.js
@@ -1,8 +1,8 @@
 const fs = require('fs');
 const path = require('path');
 
-const testsDir = path.join(__dirname, "tests");
+const testsDir = path.join(__dirname, 'tests');
 module.exports = fs.readdirSync(testsDir).map(name => ({
   name,
-  content: fs.readFileSync(path.join(testsDir, name), "utf8"),
-}));
+  content: fs.readFileSync(path.join(testsDir, name), 'utf8'),
+})).sort((a, b) => a.name.localeCompare(b.name));
diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml
index 0d9e6fc..427d7d1 100644
--- a/fuzz/Cargo.toml
+++ b/fuzz/Cargo.toml
@@ -1,5 +1,6 @@
 [package]
 name = "hyperbuild-fuzz-target"
+publish = false
 version = "0.0.1"
 authors = ["Wilson Lin <code@wilsonl.in>"]
 edition = "2018"
diff --git a/src/err.rs b/src/err.rs
index 92de9cd..12b8a8b 100644
--- a/src/err.rs
+++ b/src/err.rs
@@ -1,3 +1,5 @@
+// Implement debug to allow .unwrap().
+#[derive(Debug)]
 pub enum ErrorType {
     EntityFollowingMalformedEntity,
     NoSpaceBeforeAttr,