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The Performance Testing of ES6 Generators, ES6 Promises and Callbacks

Hi, guys. It’s going to be a short post.

I investigated the performance of the modern ES6 features and got an interesting result. For benchmarking I wrote the custom benchmark (you can try it here: GitHub). It allows to compare between each other the following features:

  • Async calls with callbacks
  • Async calls with an ES6 promise
  • Async calls with a Generator
    You can manage an amount of iterations, response time in the JS file. It’s hardcoded but exported to separated variables.

It works in a pretty simple way:

  • Draws DOM and calculates initial data
  • Starts benchmark for the first implementation
  • Try to make async action XXX times (you can define an amount of iterations)
  • Calculates time for the each iteration
  • Calculates the average value
  • Choose the second implementation…
  • Draws the results for all of the implementations

I got the following results.

Win 8.1 Chrome 51:


But there were some strange situations. Promises sometimes become slower than generators. Seems it depends on a memory amount, and this behavior is different when I trying to close some programs and minify PC overload.

Win 8.1 Firefox 47


Firefox handles generators faster than promises. And it’s a stable behavior. But firefox is stupidly slow. Seems, Mozilla should update their browser logo:


My MacBook is much less power, so I tried to run the benchmark on it too:

Chrome 51


As you can see, the picture is similar. The fastest way to make async call still be a Callback.