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README.md

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+babel-plugin-console-perf
+=========================
+
+
+A babel plugin to assist in improving JS code performance. I got this
+idea when browing documentation on various `console` methods, and
+discovered that there's a `console.profile` function that automatically
+starts and stops the JavaScript profiler for a particular region inside
+the function. I wanted to make this as seamless as possible.
+
+
+How this works
+--------------
+
+This plugin looks for the comment `// profile`, maps out the function
+region and does a couple of things:
+
+1. adds a `console.profile(<function identifier>)` method to the start of the function
+2. adds a `console.profileEnd()` right before the end of the function
+
+If there are `return` statements, it checks to see if there are
+statements/expressions there, and then re-assigns them to variables and
+returns the variable instead. This ensures that the
+statements/expressions are also profiled. For instance:
+
+
+```javascript
+
+function getHash () {
+  // profile
+  const a = 42;
+
+  return heavyCryptoFunction({ key: a });
+}
+
+```
+
+gets converted to:
+
+
+```javascript
+
+function getHash () {
+  console.profile('getHash');
+  const a = 42;
+
+  const hash = heavyCryptoFunction({ key: a});
+  console.profileEnd();
+  return hash;
+}
+
+```
+
+instead of:
+
+```javascript
+function getHash () {
+  console.profile('getHash');
+  const a = 42;
+
+  console.profileEnd();
+  return heavyCryptoFunction({ key: a });
+}
+```
+
+which misses out on profiling a potentially CPU-heavy function.