Rather than computing the ending value when the transition starts, the ending
value is computed when the transition is scheduled. This gives more predictable
behavior and makes it easier to debug evaluation errors since they occur
immediately (during user code) rather than inside a d3_timer callback.
The behavior of attrTween and styleTween are unchanged, since the interpolator
can only be constructed once the starting value is known. This commit also
removes d3.tween; I may add this back in a future commit, but I think there is
probably a better way to specify an interpolator for transitions.
The start event is now fired before any tweens are evaluated, such that you can
do any necessary preprocessing work beforehand. The end event no longer causes
the transition id to be inherited, since we can do that more elegantly now using
transition.transition.
This commit moves easing and event listeners down to the node's transition
object, allowing these fields to be modified via post-selection. This removes
the last vestige of private state for transitions.
This required a few changes to tests that depended on the order of callbacks for
tweens and events. Because timers are called back in reverse order, tweens are
now initialized in reverse order, and listeners are now invoked in order.
It is now possible to reselect elements with scheduled transitions and redefine
associated tweens; this enables "post-selection" to customize the behavior of
reusable components undergoing transitions, such as an axis. This commit also
makes it much easier to sequence transitions.
Previously, a transition's tweens were stored privately by the transition and
could only be accessed through the transition. This made it impossible to modify
transitions created by components: the transition is not accessible externally,
and cannot be reselected from the document. Consider the following snippet:
g.select(".x.axis")
.call(xAxis)
.selectAll("text")
.attr("dy", null);
If `g` is a selection, then this code alters the appearance of the axis as
expected. However, if `g` is a transition, then transition.selectAll creates a
new concurrent transition, and now multiple tweens compete to set the "dy"
attribute. Oy!
Under the new design, an element's scheduled tweens are stored semi-privately on
the node (in the existing node.__transition__). Transition parameters can thus
be reselected and modified by transitions that share the same id. If you now
reselect a transitioning element, you modify the transition rather creating a
competing transition; this should be less surprising and allow greater control.
As a side-effect of this change, it is no longer possible to schedule concurrent
transitions on the same element, even with the same id: only one transition may
be active on a given element at any time. (Note that you can still schedule
multiple future transitions on the same element, and concurrent transitions on
different elements.) For example, you could previously schedule overlapping
transitions with different easing functions, delays or durations, provided you
were careful to avoid conflict. This seems like a relatively obscure use-case
compared to modifying a transition, so I believe this is a reasonable change.
This commit also changes transition.transition, such that the returned
transition starts at the end of the originating transition, rather than
overlapping. This makes it much easier to schedule sequenced transitions without
the complexity of transition.each("end") and d3.select(this).
Also, transitions are now simply arrays of nodes, consistent with selections!
And d3.xhr now detects if the data has a type attribute; if so, this is used to
set the Content-Type header if one has not already been specified. In
conjunction with d3.urlencode, it is now easy to post encoded parameters.
This is backwards-compatible, yet adds numerous features to d3.xhr. You can now:
* Use standard node-style callbacks (fixes#473).
* Abort in-flight requests.
* Listen for progress events.
* Listen for load, error and abort events separately.
* Make POST requests (or any other method), including data.
* Set arbitrary request headers.
* Have multiple listeners on requests.
The transition-test-text callback was failing to fire when using the
latest Node.js master (82bcdbb8aaa4cf58917dc8d3fd4fcfc272512a2c). This
was most likely due to these tests being run in a different order due to
a different object enumeration order.
We weren't deleting the reference to the removed listener, so we were leaking
memory and returning a stale value on a subsequent get. Also, we now stash the
capture value when setting an event listener, so that we can automatically
remove or replace a listener without the caller needing to specify capture.
Fixes#493. Also terminates any transitions with negative or NaN durations,
rather than having them run infinitely. Also coerces NaN delays to 0 as well, to
likewise avoid infinite transitions.
This method returns the array of data for the first group in the selection. Note
that the data method cannot be used to clear data bindings, since it computes a
data join; use datum(null) to clear bound data.
Unfortunately, "delete" is a reserved word, and older browsers (such as mobile
WebKit) crash if you use reserved words as method names. I'd rather have code
that runs than strictly maintain interface-compatibility with the ES6 map.
This fixes a crash with the symbol type "hasOwnProperty", rather than defaulting
to "circle". This commit also adds new map methods to retrieve the keys, values
and entries. The map class now uses non-enumerable properties (if supported).
Jason Davies
Mike Bostock