deoncstruction-cost

A simple demo to illustrate the SIGNIFICANT performance cost of deconstruciton assignment in Javascript.

The code is in index.js and straightforward. To run:

yarn run bench
#or 
npm run bench

I see 30-40% slow down: a simple two way deconstruction assignment costs about tens of throusands CPU cycles.

My envrionment:

Macbook pro
node v8.9.3
Intel(R) Core(TM) i5-4288U CPU @ 2.60GHz

So the lessons are:

  1. Doing basic arithmatic in JS is about as efficient as in C. V8's JIT is a wonder.
  2. Beware of high level JS language constructs in highly performance sensitive code.