set multiple attributes in D3 without knowing what they are going to be ahead of time

问题

I am tying to set multiple attributes in d3 similar to what is done in this answer: https://stackoverflow.com/a/20822552/1112097, but I want to be able to pass a set of attributes in as an array so that the same code can create different elements. For example, the following data should create a red square and a green circle:

var data = [
  {
    name: "Element 1",
    type: “rect”,
    id: “rect01”,
    attributes: [
     {label: “x”, val: 0},
     {label: “y”, val: 0},
     {label: “width”, val: 10},
     {label: “height”, val: 10},
   ],
   styles: [
     {label: “fill”, val: “none”},
     {label: “stroke”, val: “#ff0000”}
   ]
 },
 {
   name: "Element 2", 
   type: “circle”,
   id: “circle01”,
   attributes: [
     {label: “cx”, val: 30},
     {label: “cy”, val: 30},
     {label: “r”, val: 10}
   ],
   styles: [
     {label: “fill”, val: “#00ff00”},
     {label: “stroke”, val: “#0000ff”}
  ]
  }
];

using something like the following:

var element = svg.selectAll(".element")
        .data(data, function(d) {return d.id;});

var elementEnter = element.enter()
        .append(function (d) {return d.type;})
        .attr("class", "element")
        .attr({
            // what goes here?
        })
        .style({
            // what goes here?
        }):

What can I put in place of "what goes here?" to set both the attribute (e.g. 'x', 'cx' or 'r') and the value using the data array.

回答1:

Try this.

function setAttributesAndStyles(d){
    var attrs = {};
    d.attributes.forEach(function(a){       
        attrs[a.label] =  a.val;
    });
    var styles = {};
    d.styles.forEach(function(a){       
        styles[a.label] =  a.val;
    });
    d3.select(this).attr(attrs);
    d3.select(this).attr(styles);
}

var element = svg.selectAll(".element")
   .data(data, function(d) {return d.id;});

var elementEnter = element.enter()
   .append(function (d) {
      return svg.append(d.type).node(); //Returns the dom element
   })        
   .attr("class", "element")
   .each(setAttributesAndStyles);

Note that selection.append(name) statement expects the name as a constant string or a function that returns the DOM element to append.

回答2:

It would be better if you changed your data to be in the following format:

   attributes: { 
     "cx": 0,
     "cy": 30,
     "r": 10
  },
   styles: {
     "fill: "#00ff00",
     "stroke": "#0000ff"
  }

This way you could simply do...

var elementEnter = element.enter()
    .append(function (d) {return d.type;})
    .attr("class", "element")
    .attr(function(d) {return d.attributes});
    .style(function(d) {return d.styles});

If you still want to keep your current format, you can do something like...

var elementEnter = element.enter()
    .append(function (d) {return d.type;})
    .attr("class", "element")
    .attr(function(d) {return arrToObj(d.attributes)});
    .style(function(d) {return arrToObj(d.styles)});

function arrToObj(arr) {
   var obj = {};
   arr.forEach(function(keyValue){
     obj[keyValue.label] = keyValue.val;
   });
   return obj;
}

来源：https://stackoverflow.com/questions/27369426/set-multiple-attributes-in-d3-without-knowing-what-they-are-going-to-be-ahead-of

标签

javascript

d3.js