html_legend_plugin.js
70 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 legendContainer = this.getLegendContainer(options) |
| 12 | let legendList = legendContainer.querySelector('ul'); |
| 13 | |
| 14 | // Create a list as needed |
| 15 | if (!legendList) { |
| 16 | legendList = document.createElement('ul'); |
| 17 | legendList.classList.add('legend-list'); |
| 18 | legendContainer.appendChild(legendList); |
| 19 | } |
| 20 | |
| 21 | // Remove old legend items |
| 22 | while (legendList.firstChild) { |
| 23 | legendList.firstChild.remove(); |
| 24 | } |
| 25 | |
| 26 | // Reuse the built-in legendItems generator |
| 27 | const items = chart.options.plugins.legend.labels.generateLabels(chart); |
| 28 | |
| 29 | items.forEach((legendData) => { |
| 30 | const id = chart.data.datasets.find((dataset) => dataset.label === legendData.text).id |
| 31 | const li = document.createElement('li'); |
| 32 | |
| 33 | li.onclick = () => { |
| 34 | const {type} = chart.config; |
| 35 | if (type === 'pie' || type === 'doughnut') { |
| 36 | // Pie and doughnut charts only have a single dataset and visibility is per item |
| 37 | chart.toggleDataVisibility(legendData.index); |
| 38 | } else { |
| 39 | chart.setDatasetVisibility(legendData.datasetIndex, !chart.isDatasetVisible(legendData.datasetIndex)); |
| 40 | } |
| 41 | chart.update(); |
| 42 | if (typeof options.callback === 'function') { |
| 43 | const visibleDatasets = chart.data.datasets.filter((dataset, index) => { |
| 44 | return chart.isDatasetVisible(index); |
| 45 | }).map((dataset) => { |
| 46 | return dataset.id |
| 47 | }) |
| 48 | options.callback(visibleDatasets) |
| 49 | } |
| 50 | }; |
| 51 | |
| 52 | li.classList.add('legend-item', `legend-item-for-${id}`) |
| 53 | |
| 54 | if (legendData.hidden) { |
| 55 | li.classList.add('hidden') |
| 56 | } |
| 57 | |
| 58 | // Color box |
| 59 | const boxSpan = document.createElement('span'); |
| 60 | |
| 61 | // Text |
| 62 | const textContainer = document.createElement('p'); |
| 63 | textContainer.textContent = legendData.text |
| 64 | |
| 65 | li.appendChild(boxSpan); |
| 66 | li.appendChild(textContainer); |
| 67 | legendList.appendChild(li); |
| 68 | }); |
| 69 | } |
| 70 | }; |