CODEWITHSUNDEEP
javascriptd3.jslistener
gefei
gefei

Reputation: 19856

d3: only two "on" possible?

Using d3.js, I have a strange issue. The following code works fine:

var zoomHandler = d3.behavior.zoom()
                        .scaleExtent([min, max])
                        .on("zoom", function() {
                            // do something;
                        }).on("zoomend", function() {
                            // do something;
                        });

But, I also want my zoomHandler to deactivate another event, so I tried to extend the code like this:

var zoomHandler = d3.behavior.zoom()
                        .scaleExtent([min, max])
                        .on("zoom", function() {
                            // do something;
                        }).on("zoomend", function() {
                            // do something;
                        }).on("otherEvent", null);

But now, at runtime, I get an exception 

Uncaught TypeError: Cannot read property 'on' of undefined

Why can I only add two listeners but not three?

Upvotes: 1

Views: 73

Answers (1)

Stephen Thomas
Stephen Thomas

Reputation: 14063

Your problem isn't with the number of events, it's the event type "otherEvent" (or whatever you're using in your code). The Zoom behavior only supports zoom events:

The following types are supported:

  • zoomstart - at the start of a zoom gesture (e.g., touchstart).
  • zoom - when the view changes (e.g., touchmove).
  • zoomend - at the end of the current zoom gesture (e.g., touchend).

Upvotes: 2

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