diff --git a/Makefile b/Makefile
index 75e5104995..24fcfe4cfc 100644
--- a/Makefile
+++ b/Makefile
@@ -262,12 +262,12 @@ build/ol-debug.js: config/ol-debug.json $(SRC_JS) $(SRC_SHADER_JS) $(SRC_SHADERL
 	@$(STAT_COMPRESSED) /tmp/ol-debug.js.gz
 	@rm /tmp/ol-debug.js.gz
 
-%shader.js: %shader.glsl src/ol/webgl/shader.mustache bin/pyglslunit.py build/timestamps/node-modules-timestamp
-	@python bin/pyglslunit.py --input $< | ./node_modules/.bin/mustache - src/ol/webgl/shader.mustache > $@
+%shader.js: %shader.glsl src/ol/webgl/shader.mustache tasks/glslunit.js build/timestamps/node-modules-timestamp
+	@node tasks/glslunit.js --input $< | ./node_modules/.bin/mustache - src/ol/webgl/shader.mustache > $@
 
-%shader/locations.js: %shader.glsl src/ol/webgl/shaderlocations.mustache bin/pyglslunit.py build/timestamps/node-modules-timestamp
+%shader/locations.js: %shader.glsl src/ol/webgl/shaderlocations.mustache tasks/glslunit.js build/timestamps/node-modules-timestamp
 	@mkdir -p $(@D)
-	@python bin/pyglslunit.py --input $< | ./node_modules/.bin/mustache - src/ol/webgl/shaderlocations.mustache > $@
+	@node tasks/glslunit.js --input $< | ./node_modules/.bin/mustache - src/ol/webgl/shaderlocations.mustache > $@
 
 .PHONY: package
 package:
diff --git a/bin/pyglslunit.py b/bin/pyglslunit.py
deleted file mode 100644
index de1b887bba..0000000000
--- a/bin/pyglslunit.py
+++ /dev/null
@@ -1,120 +0,0 @@
-#!/usr/bin/python
-
-from optparse import OptionParser
-import json
-import re
-import sys
-
-
-
-ESCAPE_SEQUENCE = {
-        '\\': '\\\\',
-        '\n': '\\n',
-        '\t': '\\t'
-        }
-
-
-def js_escape(s):
-    return ''.join(ESCAPE_SEQUENCE.get(c, c) for c in s)
-
-
-def glsl_compress(s, shortNames):
-    # strip leading whitespace
-    s = re.sub(r'\A\s+', '', s)
-    # strip trailing whitespace
-    s = re.sub(r'\s+\Z', '', s)
-    # strip multi-line comments
-    s = re.sub(r'/\*.*?\*/', '', s)
-    # strip single line comments
-    s = re.sub(r'//.*?\n', '', s)
-    # replace multiple whitespace with a single space
-    s = re.sub(r'\s+', ' ', s)
-    # remove whitespace between non-word tokens
-    s = re.sub(r'(\S)\s+([^\w])', r'\1\2', s)
-    s = re.sub(r'([^\w])\s+(\S)', r'\1\2', s)
-    # replace original names with short names
-    for originalName, shortName in shortNames.items():
-        s = s.replace(originalName, shortName)
-    return s
-
-
-def main(argv):
-    option_parser = OptionParser()
-    option_parser.add_option('--input')
-    option_parser.add_option('--output')
-    options, args = option_parser.parse_args(argv[1:])
-
-    context = {}
-    nextShortName = ord('a')
-    shortNames = {}
-
-    common, vertex, fragment = [], [], []
-    attributes, uniforms, varyings = {}, {}, {}
-    block = None
-    for line in open(options.input, 'rU'):
-        if line.startswith('//!'):
-            m = re.match(r'//!\s+NAMESPACE=(\S+)\s*\Z', line)
-            if m:
-                context['namespace'] = m.group(1)
-                continue
-            m = re.match(r'//!\s+CLASS=(\S+)\s*\Z', line)
-            if m:
-                context['className'] = m.group(1)
-                continue
-            m = re.match(r'//!\s+COMMON\s*\Z', line)
-            if m:
-                block = common
-                continue
-            m = re.match(r'//!\s+VERTEX\s*\Z', line)
-            if m:
-                block = vertex
-                continue
-            m = re.match(r'//!\s+FRAGMENT\s*\Z', line)
-            if m:
-                block = fragment
-                continue
-        else:
-            if block is None:
-                assert line.rstrip() == ''
-            else:
-                block.append(line)
-            m = re.match(r'attribute\s+\S+\s+(\S+);\s*\Z', line)
-            if m:
-                attribute = m.group(1)
-                if attribute not in attributes:
-                    shortName = chr(nextShortName)
-                    nextShortName += 1
-                    attributes[attribute] = {'originalName': attribute, 'shortName': shortName}
-                    shortNames[attribute] = shortName
-            m = re.match(r'uniform\s+\S+\s+(\S+);\s*\Z', line)
-            if m:
-                uniform = m.group(1)
-                if uniform not in uniforms:
-                    shortName = chr(nextShortName)
-                    nextShortName += 1
-                    uniforms[uniform] = {'originalName': uniform, 'shortName': shortName}
-                    shortNames[uniform] = shortName
-            m = re.match(r'varying\s+\S+\s+(\S+);\s*\Z', line)
-            if m:
-                varying = m.group(1)
-                if varying not in varyings:
-                    shortName = chr(nextShortName)
-                    nextShortName += 1
-                    shortNames[varying] = shortName
-
-    context['getOriginalFragmentSource'] = js_escape(''.join(common + fragment))
-    context['getOriginalVertexSource'] = js_escape(''.join(common + vertex))
-    context['getFragmentSource'] = glsl_compress(''.join(common + fragment), shortNames)
-    context['getVertexSource'] = glsl_compress(''.join(common + vertex), shortNames)
-    context['getAttributes'] = [attributes[a] for a in sorted(attributes.keys())]
-    context['getUniforms'] = [uniforms[u] for u in sorted(uniforms.keys())]
-
-    if options.output and options.output != '-':
-        output = open(options.output, 'wb')
-    else:
-        output = sys.stdout
-    json.dump(context, output)
-
-
-if __name__ == '__main__':
-    sys.exit(main(sys.argv))
diff --git a/tasks/glslunit.js b/tasks/glslunit.js
new file mode 100644
index 0000000000..236719951c
--- /dev/null
+++ b/tasks/glslunit.js
@@ -0,0 +1,146 @@
+const fs = require('fs');
+
+const ESCAPE_SEQUENCE = {
+  '\\': '\\\\',
+  '\n': '\\n',
+  '\t': '\\t'
+};
+
+function js_escape(s) {
+  return s.split('').map(function(c) {
+    return ESCAPE_SEQUENCE[c] || c;
+  }).join('');
+}
+
+function glsl_compress(s, shortNames) {
+  // strip leading whitespace
+  s = s.replace(/^\s+/g, '');
+  // strip trailing whitespace
+  s = s.replace(/\s+$/g, '');
+  // strip multi-line comments
+  s = s.replace(/\/\*[\s\S]*?\*\//g, '');
+  // strip single line comments
+  s = s.replace(/\/\/.*?\n/, '');
+  // replace multiple whitespace with a single space
+  s = s.replace(/\s+/g, ' ');
+  // remove whitespace between non-word tokens
+  s = s.replace(/(\S)\s+([^\w])/g, '$1$2')
+      .replace(/([^\w])\s+(\S)/g, '$1$2');
+  // replace original names with short names
+  for (var originalName in shortNames) {
+    s = s.replace(new RegExp(originalName, 'gm'), shortNames[originalName]);
+  }
+  return s;
+}
+
+function main(argv) {
+  var options = {};
+  for (var i = 2, ii = argv.length; i < ii; i += 2) {
+    options[argv[i].replace(/^../, '')] = argv[i + 1];
+  }
+  if (!options.input) {
+    process.stdout.write('--input option missing\n');
+    return 1;
+  }
+
+  const json = {};
+  let nextShortName = 'a'.charCodeAt(0);
+  const shortNames = {};
+
+  const attributes = {};
+  const uniforms = {};
+  const varyings = {};
+  const blocks = {
+    common: '',
+    vertex: '',
+    fragment: ''
+  };
+  let block = undefined;
+  const inFile = fs.readFileSync(options.input, 'utf-8');
+  const lines = inFile.split('\n');
+
+  let m, shortName;
+  lines.forEach(function(line, i) {
+    if (line.indexOf('//!') == 0) {
+      m = line.match(/\/\/!\s+NAMESPACE=(\S+)\s*$/);
+      if (m) {
+        json.namespace = m[1];
+        return;
+      }
+      m = line.match(/\/\/!\s+COMMON\s*$/);
+      if (m) {
+        block = 'common';
+        return;
+      }
+      m = line.match(/\/\/!\s+VERTEX\s*$/);
+      if (m) {
+        block = 'vertex';
+        return;
+      }
+      m = line.match(/\/\/!\s+FRAGMENT\s*$/);
+      if (m) {
+        block = 'fragment';
+        return;
+      }
+    } else {
+      if (block === undefined) {
+        if (line.replace(/\s+$/g, '') != '') {
+          process.stdout.write(`Error parsing ${options.input}\n`);
+          return;
+        }
+      } else {
+        blocks[block] += line + (i == lines.length - 1 ? '' : '\n');
+      }
+      m = line.match(/attribute\s+\S+\s+(\S+);\s*$/);
+      if (m) {
+        const attribute = m[1];
+        if (!(attribute in attributes)) {
+          shortName = String.fromCharCode(nextShortName++);
+          attributes[attribute] = {
+            originalName: attribute,
+            shortName: shortName
+          };
+          shortNames[attribute] = shortName;
+        }
+      }
+      m = line.match(/uniform\s+\S+\s+(\S+);\s*$/);
+      if (m) {
+        const uniform = m[1];
+        if (!(uniform in uniforms)) {
+          shortName = String.fromCharCode(nextShortName++);
+          uniforms[uniform] = {
+            originalName: uniform,
+            shortName: shortName
+          };
+          shortNames[uniform] = shortName;
+        }
+      }
+      m = line.match(/varying\s+\S+\s+(\S+);\s*$/);
+      if (m) {
+        const varying = m[1];
+        if (!(varying in varyings)) {
+          shortName = String.fromCharCode(nextShortName++);
+          shortNames[varying] = shortName;
+        }
+      }
+    }
+  });
+
+  json.originalFragmentSource = js_escape(blocks.common + blocks.fragment);
+  json.originalVertexSource = js_escape(blocks.common + blocks.vertex);
+  json.fragmentSource = glsl_compress(blocks.common + blocks.fragment, shortNames);
+  json.vertexSource = glsl_compress(blocks.common + blocks.vertex, shortNames);
+  json.attributes = Object.keys(attributes).map(a => attributes[a]);
+  json.uniforms = Object.keys(uniforms).map(u => uniforms[u]);
+
+  if (options.output && options.output != '-') {
+    fs.writeFileSync(options.output, JSON.stringify(json));
+  } else {
+    process.stdout.write(JSON.stringify(json));
+  }
+  return 0;
+}
+
+if (require.main === module) {
+  process.exit(main(process.argv));
+}