[英]Javascript or D3js Notation
How is there an assignment operator in the OR function. OR函数中如何有赋值运算符。
What would be the result of each of the two return statements. 这两个return语句中的每一个的结果将是什么。
Refer: http://www.d3noob.org/2014/01/tree-diagrams-in-d3js_11.html 请参阅: http : //www.d3noob.org/2014/01/tree-diagrams-in-d3js_11.html
var node = svg.selectAll("g.node")
.data(nodes, function(d) { return d.id || (d.id = ++i); });
nodeEnter.append("text")
.attr("x", function(d) {
return d.children || d._children ? -13 : 13; })
in your example, usually it is the way used to define unique index in d3 在您的示例中,通常这是在d3中定义唯一索引的方法
var node = svg.selectAll("g.node")
.data(nodes, function(d) { return d.id || (d.id = ++i); });
//here if d.id exists and is truthy, just return d.id; if not, then assign d.id to ++i
second is same: 第二个是相同的:
if d.children is (defined and truthy value) then return -13
if d.children is not defined or is falsy then return 13
(For reference: "Truthy" and "Falsy" Values ) (供参考: “ Truthy”和“ Falsy”值 )
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