javascriptのバーティカルバーの意味
javascriptに関して質問させて頂きます。宜しくお願い申し上げます。
D3jsの勉強をしているのですが、以下のサンプルで、
links.forEach(function(link) {
link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
});
このコードのしていることがよくわかりません。
処理後の結果を見ると何をしているのかが何となく分かるのですが、特にバーティカルバーでつないでいる式が何を意味するのかが分かりません。
比較演算子のようにも思えますが、処理の優先度を決めている?のかなあとも思いつつ、理解できませんでした。
詳しい方がいらっしゃいましたら、是非、ご教示願います。
https://gist.github.com/mbostock/1153292
var links = [
{source: "Microsoft", target: "Amazon", type: "licensing"},
{source: "Microsoft", target: "HTC", type: "licensing"},
{source: "Samsung", target: "Apple", type: "suit"},
{source: "Motorola", target: "Apple", type: "suit"},
{source: "Nokia", target: "Apple", type: "resolved"},
{source: "HTC", target: "Apple", type: "suit"},
{source: "Kodak", target: "Apple", type: "suit"},
{source: "Microsoft", target: "Barnes & Noble", type: "suit"},
{source: "Microsoft", target: "Foxconn", type: "suit"},
{source: "Oracle", target: "Google", type: "suit"},
{source: "Apple", target: "HTC", type: "suit"},
{source: "Microsoft", target: "Inventec", type: "suit"},
{source: "Samsung", target: "Kodak", type: "resolved"},
{source: "LG", target: "Kodak", type: "resolved"},
{source: "RIM", target: "Kodak", type: "suit"},
{source: "Sony", target: "LG", type: "suit"},
{source: "Kodak", target: "LG", type: "resolved"},
{source: "Apple", target: "Nokia", type: "resolved"},
{source: "Qualcomm", target: "Nokia", type: "resolved"},
{source: "Apple", target: "Motorola", type: "suit"},
{source: "Microsoft", target: "Motorola", type: "suit"},
{source: "Motorola", target: "Microsoft", type: "suit"},
{source: "Huawei", target: "ZTE", type: "suit"},
{source: "Ericsson", target: "ZTE", type: "suit"},
{source: "Kodak", target: "Samsung", type: "resolved"},
{source: "Apple", target: "Samsung", type: "suit"},
{source: "Kodak", target: "RIM", type: "suit"},
{source: "Nokia", target: "Qualcomm", type: "suit"}
];
var nodes = {};
// Compute the distinct nodes from the links.
links.forEach(function(link) {
link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
});