Problems parsing data with the D3.js Sankey layout - d3.js

Question

I'm looking for some hints as to what I am doing wrong with a Sankey diagram I'm creating. I am charting changes in food consumption over time, and using the Sankey layout to visualize how these values changed over a period of forty years.
The bl.ock and small dataset are here. The relevant code:
var margin = {top: 1, right: 1, bottom: 6, left: 1},
width = 1260 - margin.left - margin.right,
height = 1000 - margin.top - margin.bottom;
var formatNumber = d3.format(",.0f"),
format = function(d) { return formatNumber(d) + " TWh"; },
color = d3.scale.category20();
var svg = d3.select("#chart").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var sankey = d3.sankey()
.nodeWidth(15)
.nodePadding(10)
.size([width, height]);
var path = sankey.link();
// ========================== Prepare data ==========================
queue()
.defer(d3.csv, "grains.csv")
.await(ready);
// ========================== Start viz ==========================
function ready(error, csv_data) {
nodes = [];
edges = [];
nodesArray = [];
// Scales
yearScale = d3.scale.linear().domain([1640,1688]).range([20,width -20]);
radiusScale = d3.scale.linear().domain([0,300]).range([2,12]).clamp(true);
chargeScale = d3.scale.linear().domain([0,100]).range([0,-100]).clamp(true);
uniqueValues = d3.set(nodesArray.map(function(d) {return d.name})).values();
colorScale = d3.scale.category20b(uniqueValues);
sortScale = d3.scale.ordinal().domain(uniqueValues).rangePoints([-0.001,.001]);
// Create a JSON link array
// This creates unique nodes for each item and its corresponding date.
// For example, nodes are rendered as "peas-1640," "peas-1641," etc.
csv_data.forEach(function(link) {
key = link.translation + '-' + link.date;
link.source = nodes[key] || (nodes[key] = {name: link.translation, date: link.date, origX: yearScale(parseInt(link.date)), value: link.value || 0});
});
// Build the edgesArray array
// This creates the edgesArray to correspond with unique nodes. We're telling
// items and dates to remain together. So, the code below tells the graph
// layout that `1641` is preceded by `1640` and followed by `1642`, etc.
var y = "→";
for (x in nodes) {
nodesArray.push(nodes[x])
if(nodes[y]) {
nodes[y].date = parseInt(nodes[y].date);
if (nodes[y].name == nodes[x].name) {
var newLink = {source:nodes[y], target:nodes[x]}
edges.push(newLink);
}
}
y = x;
}
sankey
.nodeWidth(10)
.nodePadding(10)
.size([1200, 1200])
.nodes(nodesArray.filter(function(d,i) {return d.date < 1650}))
.links(edges.filter(function(d,i) { return i < 50 && d.source.date < 1650 && d.target.date < 1650} )) // filtering to test a smaller data set
.layout(32);
var link = svg.append("g").selectAll(".link")
.data(edges.filter(function(d,i) { return i < 50 && d.source.date < 1650 && d.target.date < 1650} )) // filtering to test a smaller data set
.enter().append("path")
.attr("class", "link")
.attr("d", path)
.style("stroke-width", function(d) { return Math.max(1, d.dy); })
.sort(function(a, b) { return b.dy - a.dy; });
link.append("title")
.text(function(d) { return d.source.name + " → " + d.target.name + "\n" + format(d.value); });
var node = svg.append("g").selectAll(".node")
.data(nodesArray.filter(function(d,i) {return d.date < 1650})) // filtering to test a smaller data set
.enter().append("g")
.attr("class", "node")
.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; })
.call(d3.behavior.drag()
.origin(function(d) { return d; })
.on("dragstart", function() { this.parentNode.appendChild(this); })
.on("drag", dragmove));
node.append("rect")
.attr("height", function(d) { return d.dy; })
.attr("width", sankey.nodeWidth())
.style("fill", function(d) { return d.color = color(d.name.replace(/ .*/, "")); })
.style("stroke", function(d) { return d3.rgb(d.color).darker(2); })
.append("title")
.text(function(d) { return d.name + "\n" + format(d.value); });
node.append("text")
.attr("x", -6)
.attr("y", function(d) { return d.dy / 2; })
.attr("dy", ".35em")
.attr("text-anchor", "end")
.attr("transform", null)
.text(function(d) { return d.name; })
.filter(function(d) { return d.x < width / 2; })
.attr("x", 6 + sankey.nodeWidth())
.attr("text-anchor", "start");
function dragmove(d) {
d3.select(this).attr("transform", "translate(" + d.x + "," + (d.y = Math.max(0, Math.min(height - d.dy, d3.event.y))) + ")");
sankey.relayout();
link.attr("d", path);
}
};
Unfortunately, I'm getting an error as you can see in the bl.ock. The Boss suggested it might be a circular link but I'm at a bit of a loss. Any hints or suggestions?
EDIT: For some clarity, I'm after something like this:
(Source)
From what I can tell, I think I'm building the nodes and edges correctly. If we look at the console for the nodes array and edges array:
It's not like a usual Sankey or alluvial diagram, which, as I've often seen them, shows collapses and expansions of items. In my case the date, food item, and value are all a single stream throughout the length of the visualization but are resized/repositioned based on the value for a given year (like the example image above).