html_legend_plugin.js
73 lines
| 1 | module.exports = { |
| 2 | id: 'htmlLegend', |
| 3 | getLegendContainer(options) { |
| 4 | if (options.container instanceof HTMLElement) { |
| 5 | return options.container |
| 6 | } else { |
| 7 | return document.getElementById(options.containerID); |
| 8 | } |
| 9 | }, |
| 10 | afterUpdate(chart, args, options) { |
| 11 | const shouldAnimate = options.shouldAnimate ?? true; |
| 12 | const legendContainer = this.getLegendContainer(options) |
| 13 | let legendList = legendContainer.querySelector('ul'); |
| 14 | |
| 15 | // Create a list as needed |
| 16 | if (!legendList) { |
| 17 | legendList = document.createElement('ul'); |
| 18 | legendList.classList.add('legend-list'); |
| 19 | legendContainer.appendChild(legendList); |
| 20 | } |
| 21 | |
| 22 | // Remove old legend items |
| 23 | while (legendList.firstChild) { |
| 24 | legendList.firstChild.remove(); |
| 25 | } |
| 26 | |
| 27 | // Reuse the built-in legendItems generator |
| 28 | const items = chart.options.plugins.legend.labels.generateLabels(chart); |
| 29 | |
| 30 | items.forEach((legendData) => { |
| 31 | const id = chart.data.datasets.find((dataset) => dataset.label === legendData.text).id |
| 32 | const li = document.createElement('li'); |
| 33 | |
| 34 | li.onclick = () => { |
| 35 | const {type} = chart.config; |
| 36 | if (type === 'pie' || type === 'doughnut') { |
| 37 | // Pie and doughnut charts only have a single dataset and visibility is per item |
| 38 | chart.toggleDataVisibility(legendData.index); |
| 39 | } else { |
| 40 | chart.setDatasetVisibility(legendData.datasetIndex, !chart.isDatasetVisible(legendData.datasetIndex)); |
| 41 | } |
| 42 | |
| 43 | chart.update(shouldAnimate ? null : 'none'); |
| 44 | |
| 45 | if (typeof options.callback === 'function') { |
| 46 | const visibleDatasets = chart.data.datasets.filter((dataset, index) => { |
| 47 | return chart.isDatasetVisible(index); |
| 48 | }).map((dataset) => { |
| 49 | return dataset.id |
| 50 | }) |
| 51 | options.callback(visibleDatasets) |
| 52 | } |
| 53 | }; |
| 54 | |
| 55 | li.classList.add('legend-item', `legend-item-for-${id}`) |
| 56 | |
| 57 | if (legendData.hidden) { |
| 58 | li.classList.add('hidden') |
| 59 | } |
| 60 | |
| 61 | // Color box |
| 62 | const boxSpan = document.createElement('span'); |
| 63 | |
| 64 | // Text |
| 65 | const textContainer = document.createElement('p'); |
| 66 | textContainer.textContent = legendData.text |
| 67 | |
| 68 | li.appendChild(boxSpan); |
| 69 | li.appendChild(textContainer); |
| 70 | legendList.appendChild(li); |
| 71 | }); |
| 72 | } |
| 73 | }; |