create emit before we use it; make move accept an event.

[Fil]

This seems to:

• fix Error multitouch emit undefined inside move function #83
• possibly fix Does not receive "end" event after pressing right mouse button during drag & drop with left button d3-zoom#198
• help with Brush & zoom d3-zoom#222

[mbostock]

It doesn’t feel appropriate to use the event here because time has passed—we’re now inside a transition.

[lauvigne]

Hello,

with 3.0.0, I have this following error,
ERROR TypeError: emitter(...).moved is not a function at SVGGElement.touchmoved (brush.js:581:1)
And
core.js:6479 ERROR TypeError: emitter(...).ended is not a function at SVGGElement.touchended (brush.js:585:1)

Is it a similar problem of this fix ?

on :
`function touchmoved(event) {
emitter(this, arguments).moved(event);
}

function touchended(event) {
emitter(this, arguments).ended(event);
}`

[Fil]

Hard to tell—can you give a bit more context?

[lauvigne]

I have this error on a brush with a filter.
Theses errors arrive on mobile with touch event, not in my code but in the brush.js.

`this.brush = d3Brush
.brush()
.filter(event => event.touches?.length === 2)
.extent([
[0, 0],
[this.context.width, this.height],
])
.on('end', this.brushEnded.bind(this));

this.graphique.append('g').attr('class', 'brush').attr('id', this.indexGraphe).call(this.brush);
`

I will try to do with your sample to reproduce.

Thanks

[Fil]

I think maybe .filter(event => event.touches?.length === 2) is filtering out the events that start the gesture? In that case I can see how you would get into this situation where the emitter has not been "blessed" with a touchended property

[lauvigne]

OK ! I understood...So It's perhaps a problem with this filter.
Thanks Fil.

I will investigate on a workaround.