Unit

README.markdown

Unit.coffee

A quick scripts to support basic unit conversion in coffeescript and javascript. All you have to do is put one way conversion from one unit to another (for example: s to ms is 1000) and Unit.coffee handles bridging units (like converting ms to m) and going backwards in units. It does not yet support more complex conversions but this can be added by allowing a function to be set as the conversion factor (passing it a number, and whether it's forwards or reverse)

Unit.coffee

conversion=
    "h m":60,
    "m s":60,
    "s ms":1000

path=(from,to)->
    for c of conversion
        if ~(" "+c+" ").indexOf(" "+from+" ")
            c=c.split " ";
            if c[0] is from
                if conversion["#{c[1]} #{to}"]
                    c.push(to)
                    return c
                else
                    return c.slice(0,-1).concat path c[1], to
    throw "Cannot convert unit #{from} to unit #{to}.";

@Unit=class Unit
    constructor:(@v, @u)->
    convert:(u)->
        return this if u is @u
        if c=conversion[@u+" "+u]
            v=@v*c
        else if c=conversion[u+" "+@u]
            v=@v*(1/c)
        else
            v=this
            for un in path @u,u
                v=v.convert(un) 
            v=v.v;
        new Unit v, u;
    toString:->
        @v+@u