如何使用d3.js以编程方式触发拖动事件? [英] How to programmatically trigger drag events with d3.js?
问题描述
我写了一些对SVG元素使用拖动事件的代码.该代码工作正常,我想为此编写一些测试.与其手动手动移动鼠标,不如通过编程方式使用
I wrote some code that uses a drag event for svg elements. The code works fine and I would like to write some tests for it. Instead of manually moving my mouse by hand I would like to programmatically trigger the dragstart
and drag
events with selection.dispatch:
svgSelection.dispatch('dragstart',{bubbles:true});
svgSelection.dispatch('drag',{bubbles:true});
但是,事件似乎没有被触发.也许我使用了错误的事件键,或者需要包含一些其他选项?
However, the events do not seem to be fired. Maybe I use the wrong event keys or need to include some additional option?
我还尝试使用以下无济于事的变体:
I also tried to use following variants that did not help:
svgElement.dispatchEvent(new Event('drag', {bubbles:true}));
svgSelection.dispatch('mousedown.drag',{bubbles:true});
如果我尝试
svgElement.on('mousedown.drag')()
我得到一个错误
Uncaught TypeError: Cannot read property 'ctrlKey' of null
at defaultFilter (drag.js?009f:10)
at mousedowned (drag.js?009f:51)
触发以下代码中使用的事件开始"和拖动"的正确方法是什么?
What is the right way to trigger the events 'start' and 'drag' used in following code?
let offset = [0,0];
let drag = d3.drag()
.on('start', () => this.__dragStarted(d3, svgSelection, offset))
.on('drag', ()=> this.__dragged(d3, svgSelection, offset));
svgSelection.call(drag);
我的测试示例:
it('enableDragAndDrop', ()=>{
let element = document.createElement('svg');
let svgSelection = d3.select(element);
spyOn(sut, '__dragStarted');
spyOn(sut, '__dragged');
sut.enableDragAndDrop(svgSelection);
svgSelection.dispatch('dragstart',{bubbles:true});
svgSelection.dispatch('drag',{bubbles:true});
expect(sut.__dragStarted).toHaveBeenCalled();
expect(sut.__dragged).toHaveBeenCalled();
});
我的代码示例:
enableDragAndDrop(svgSelection){
let offset = [0,0];
let drag = d3.drag()
.on('start', () => this.__dragStarted(d3, svgSelection, offset))
.on('drag', ()=> this.__dragged(d3, svgSelection, offset));
svgSelection.call(drag);
}
__dragStarted(d3, svgSelection, offset){
if(!svgSelection.attr('transform')){
svgSelection.attr('transform','translate(0,0)');
}
let transform = svgSelection.attr('transform');
let translate = this.__extractTranslate(transform);
offset[0] = translate[0] - d3.event.x;
offset[1] = translate[1] - d3.event.y;
}
__dragged(d3, svgSelection, offset){
let x = d3.event.x + offset[0];
let y = d3.event.y + offset[1];
svgSelection
.attr('transform', 'translate(' + x + ', ' + y + ')');
}
__extractTranslate(transformString){
let stripped = transformString;
stripped = stripped.replace('translate(','');
stripped = stripped.replace(')','');
let numberStrings = stripped.split(',');
return numberStrings.map(numberString=>parseFloat(numberString));
}
相关问题:
推荐答案
下面是一项工作,该工作部分用笑话模拟了d3:
Here is a work around that partially mocks d3 with jest:
import * as d3 from 'd3';
jest.mock('d3', ()=>{
let wrappedD3 = jest.requireActual('d3');
var d3Mock = {
drag: undefined,
event: wrappedD3.event,
select: wrappedD3.select,
__passedEventHandlers: []
};
d3Mock.drag = ()=>{
let dragMock = {
apply: ()=>{}
};
dragMock.on = (event, eventHandler)=>{
d3Mock.__passedEventHandlers.push(eventHandler);
return dragMock;
}
return dragMock;
};
return d3Mock;
});
测试中的用法示例:
it('enableDragAndDrop', ()=>{
let element = document.createElement('svg');
document.body.appendChild(element);
let svgSelection = d3.select(element);
sut.enableDragAndDrop(svgSelection);
spyOn(sut, '__dragStarted');
let dragStartedHandler = d3.__passedEventHandlers[0];
dragStartedHandler();
expect(sut.__dragStarted).toHaveBeenCalled();
spyOn(sut, '__dragged');
let draggedHandler = d3.__passedEventHandlers[1];
draggedHandler();
expect(sut.__dragged).toHaveBeenCalled();
});
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