Style question: bracket notation vs dot notation

[samreid]

In gravity and orbits code, I am seeing several instances that use the bracket notation for property access:

model[currentObj + 'Position'] = model[currentObj + 'Position'].timesScalar( 1.0 / scale ).plus( model[currentObj + 'Velocity'].timesScalar( dt ).plus( model[currentObj + 'Acceleration'].timesScalar( dt * dt / 2.0 ) ) ).timesScalar( scale );

instead of the dot notation, here is the above rewritten with dot notation:

body.position = body.position.timesScalar( 1.0 / scale ).plus( body.velocity ).timesScalar( dt ).plus( body.acceleration ).timesScalar( dt * dt / 2 ).timesScalar( scale );

The latter (dot notation) is more consistent with the style we use throughout the rest of our code base, and it seems to me a bit easier to read. Is there a good reason to use the bracket notation? Should the sim be converted to use dot notation?

[samreid]

It looks performance characteristics are about the same on many platforms, with a notable speed improvement on Safari: http://jsperf.com/dot-notation-vs-bracket-notation/2

This amount of speed increase for safari may be in the noise compared to more expensive steps like drawing.

[samreid]

The most upvoted answer in Stack Overflow's "JavaScript property access: dot notation vs. brackets?" question concludes:

Dot notation is faster to write and clearer to read.
Square bracket notation allows access to properties containing special characters and selection of properties using variables

http://stackoverflow.com/questions/4968406/javascript-property-access-dot-notation-vs-brackets

[jbphet]

I agree that dot notation is more readable, so I would like to see us standardize on it and only use bracket notation when it is necessary to do so.

[jonathanolson]

Your jsperf didn't include the string concatenations (and thus JIT dynamic lookups that in the jsperf can be compiled to static references) that are going in in the above code. I think the dot notation will be faster in that specific case, and I prefer the dot notation style.

[pixelzoom]

+1 for dot notation. I especially don't like the style of bracket notation that uses string concatenation.