Refactored .toString() to improve speed

CHANGELOG.md

@@ -6,6 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [2.5.0] - WIP
+### Changed
+- Refactored `.toString()` to improve speed.
+
+
 ## [2.4.1] - 2022-01-03
 ### Fixed
 - Fixed TS definition (regression in 2.4.0), #57.
@@ -155,6 +160,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - First release.
 
 
+[2.5.0]: https://github.com/fontello/svgpath/compare/2.4.1...2.5.0
 [2.4.1]: https://github.com/fontello/svgpath/compare/2.4.0...2.4.1
 [2.4.0]: https://github.com/fontello/svgpath/compare/2.3.1...2.4.0
 [2.3.1]: https://github.com/fontello/svgpath/compare/2.3.0...2.3.1

benchmark/benchmark.js

@@ -20,12 +20,6 @@ fs.readdirSync(IMPLS_DIRECTORY).sort().forEach(name => {
   IMPLS.push({ name, code });
 });
 
-
-const SAMPLES = {
-  big: fs.readFileSync(path.join(__dirname, 'samples/big.txt'), 'utf8'),
-  one_path: fs.readFileSync(path.join(__dirname, 'samples/one_path.txt'), 'utf8')
-};
-
 let suite;
 
 function run(suite) {
@@ -36,6 +30,13 @@ function run(suite) {
     .run();
 }
 
+
+const SAMPLES = {
+  big: fs.readFileSync(path.join(__dirname, 'samples/big.txt'), 'utf8'),
+  one_path: fs.readFileSync(path.join(__dirname, 'samples/one_path.txt'), 'utf8')
+};
+
+
 suite = new Benchmark.Suite('.from("big.txt")');
 
 IMPLS.forEach(impl => {
@@ -53,6 +54,7 @@ IMPLS.forEach(impl => {
 
 run(suite);
 
+
 const long = 'M 4.8173765432098765 -9.12666320366964 Z'.repeat(5000);
 
 suite = new Benchmark.Suite('.from(long).toString()');

lib/svgpath.js

@@ -187,26 +187,42 @@ SvgPath.prototype.__evaluateStack = function () {
 // Convert processed SVG Path back to string
 //
 SvgPath.prototype.toString = function () {
-  var elements = [], skipCmd, cmd;
+  var result = '', prevCmd = '', cmdSkipped = false;
 
   this.__evaluateStack();
 
-  for (var i = 0; i < this.segments.length; i++) {
-    // remove repeating commands names
-    cmd = this.segments[i][0];
-    skipCmd = i > 0 && cmd !== 'm' && cmd !== 'M' && cmd === this.segments[i - 1][0];
-    elements = elements.concat(skipCmd ? this.segments[i].slice(1) : this.segments[i]);
+  for (var i = 0, len = this.segments.length; i < len; i++) {
+    var segment = this.segments[i];
+    var cmd = segment[0];
+
+    // Command not repeating => store
+    if (cmd !== prevCmd || cmd === 'm' || cmd === 'M') {
+      // workaround for FontForge SVG importing bug, keep space between "z m".
+      if (cmd === 'm' && prevCmd === 'z') result += ' ';
+      result += cmd;
+
+      cmdSkipped = false;
+    } else {
+      cmdSkipped = true;
+    }
+
+    // Store segment params
+    for (var pos = 1; pos < segment.length; pos++) {
+      var val = segment[pos];
+      // Space can be skipped
+      // 1. After command (always)
+      // 2. For negative value (with '-' at start)
+      if (pos === 1) {
+        if (cmdSkipped && val >= 0) result += ' ';
+      } else if (val >= 0) result += ' ';
+
+      result += val;
+    }
+
+    prevCmd = cmd;
   }
 
-  return elements.join(' ')
-    // Optimizations: remove spaces around commands & before `-`
-    //
-    // We could also remove leading zeros for `0.5`-like values,
-    // but their count is too small to spend time for.
-    .replace(/ ?([achlmqrstvz]) ?/gi, '$1')
-    .replace(/ \-/g, '-')
-    // workaround for FontForge SVG importing bug
-    .replace(/zm/g, 'z m');
+  return result;
 };