A quick illustration of the compact and readable nature of iteration with reducers

red.js

/*
  This gist is just a quick example of the same function written
  in a composable manner (using prodash.js).  Please understand 
  that the functions exported by prodash are almost ALL curried 
  by default allowing them to be partially applied.  
  
  The goal of this code is to iterate through a list of "particles"
  and return a Float32Array of their x,y,z components.  Only living
  particles should be included.
*/

//declarative or "point free" style
let Float32s       = (arg) => new Float32Array(arg)
let flatPositions  = compose([checking("living"), plucking("position"), cat])
let positionsArray = compose([Float32s, sequence(flatPositions)])

//here we get our result
let positions = positionsArray(particles)

//imperative style
let buildFlatPositions (particles) => {
  let out = []
  let particle
  
  for (let i = 0; i < particles.length; ++i) {
    particle = particles[i]
    if (!!particle.living) {
      out.push(particle.position[0])
      out.push(particle.position[1])
      out.push(particle.position[2])
    }
  }
  return new Float32Array(out)
}

//result
let positions = buildFlatPositions(particles)