selection.merge(transition…)? #257
Description
d3-selection@2 release notes mention:
selection.merge(transition) now throws an error to make it more obvious when you attempt to merge a selection with something that’s not, say because you mistakenly returned a transition from your selection.join’s update function.
However thanks to #248 selection.merge could call transition|selection.selection() before merging.
This would simplify a lot the examples in https://observablehq.com/@d3/selection-join.
svg.selectAll("text")
.data(randomLetters(), d => d)
.join(
enter => enter.append("text")
.attr("fill", "green")
.attr("x", (d, i) => i * 16)
.attr("y", -30)
.text(d => d)
.transition(t)
.attr("y", 0), // 🧨
update => update
.attr("fill", "black")
.attr("y", 0)
.transition(t)
.attr("x", (d, i) => i * 16), // 🧨
exit => exit
.attr("fill", "brown")
.transition(t)
.attr("y", 30)
.remove()
);Note that we can already do:
svg.selectAll("text")
.data(randomLetters(), d => d)
.join(
enter => enter.append("text")
.attr("fill", "green")
.attr("x", (d, i) => i * 16)
.attr("y", -30)
.text(d => d)
.transition(t)
.attr("y", 0)
.selection(), // 🤘
update => update
.attr("fill", "black")
.attr("y", 0)
.transition(t)
.attr("x", (d, i) => i * 16)
.selection(), // 🤘
exit => exit
.attr("fill", "brown")
.transition(t)
.attr("y", 30)
.remove()
);