d3-view/src/directives/attr.js

import { isArray } from "d3-let";
import properties from "../utils/htmlprops";

//
//  d3-attr-<attr> directive
//  ==============================
//
//  Create a one-way binding between a model and a HTML element attribute
//
export default {
  create(expression) {
    if (!this.arg)
      return this.logWarn(
        "Cannot bind to empty attribute. Specify :<attr-name>"
      );
    return expression;
  },

  refresh(model, value) {
    if (this.arg === "class") return this.refreshClass(value);
    if (isArray(value))
      return this.logWarn(`Cannot apply array to attribute ${this.arg}`);
    var prop = properties.get(this.arg);
    if (prop) this.sel.property(prop, value || false);
    else this.sel.attr(this.arg, value || null);
  },

  refreshClass(value) {
    var sel = this.sel;

    if (!isArray(value)) value = [value];

    if (this.oldValue)
      this.oldValue.forEach(entry => {
        if (entry) sel.classed(entry, false);
      });

    this.oldValue = value.map(entry => {
      var exist = true;
      if (isArray(entry)) {
        exist = entry[1];
        entry = entry[0];
      }
      if (entry) sel.classed(entry, exist);
      return entry;
    });
  }
};