Even, whole element width with even, whole margin

even-width.js

var fullWidth = 290
var numberOfElements = 7
var positionOffset = 0

process.argv.forEach(function(arg) {
    var offsetRegexp = /--offset=(\d+)/
    if (offsetRegexp.test(arg))
        positionOffset = parseInt(arg.replace(offsetRegexp, '$1'))
})

var elementWidth = findWidth(fullWidth, numberOfElements)
var margin = getMargin(fullWidth, numberOfElements, elementWidth)
var message = 'Could not find an even width for ' + numberOfElements + ' elements in a space with width of ' + fullWidth
if (margin != null)
    message = fullWidth + ' is evenly distributed among ' + numberOfElements  + ' elements sharing width of ' + elementWidth + ', with a margin of ' + margin
console.log(message)
var positioning = []
for (var i = 0; i < numberOfElements; i++) {
    var relativePosition = ((elementWidth * i) + (margin * i))
    positioning.push(positionOffset + relativePosition)
}
console.log('elements begin at positions: ', positioning)

function findWidth(fullWidth, numberOfElements, currWidth) {
    currWidth = currWidth || Math.floor((fullWidth / numberOfElements))
    if (currWidth < 0)
        return null
    currMargin = getMargin(fullWidth, numberOfElements, currWidth)
    if ((currMargin % 1) !== 0)
        return findWidth(fullWidth, numberOfElements, (currWidth - 1))
    return currWidth
}

function getMargin(fullWidth, numberOfElements, elementWidth) {
    return ((fullWidth - (numberOfElements * elementWidth)) / (numberOfElements - 1))
}