Currently, I am involved in a project that requires the implementation of various charts from the Vue-Chartjs library. One specific requirement is to dynamically change the maximum value on the Y-axis whenever users apply different filters. To achieve this, I have imported an existing barchart component from the vue-chartjs library. The code includes a JavaScript file with pre-defined defaults, and for customization, I can utilize the extraOptions object as a prop to tailor each chart accordingly. Here is the default component structure:
import { Bar } from 'vue-chartjs'
import { hexToRGB } from "./utils";
import reactiveChartMixin from "./mixins/reactiveChart";
let defaultOptions = {
tooltips: {
tooltipFillColor: "rgba(0,0,0,0.5)",
tooltipFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
tooltipFontSize: 14,
tooltipFontStyle: "normal",
tooltipFontColor: "#fff",
tooltipTitleFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
tooltipTitleFontSize: 14,
tooltipTitleFontStyle: "bold",
tooltipTitleFontColor: "#fff",
tooltipYPadding: 6,
tooltipXPadding: 6,
tooltipCaretSize: 8,
tooltipCornerRadius: 6,
tooltipXOffset: 10,
},
legend: {
display: false
},
scales: {
yAxes: [{
ticks: {
fontColor: "#9f9f9f",
fontStyle: "bold",
beginAtZero: true,
display: false,
min: 0,
max: 100
},
gridLines: {
display: false,
drawBorder: false,
}
}],
xAxes: [{
gridLines: {
display: false,
drawBorder: false,
},
}],
}
};
export default {
name: 'BarChart',
extends: Bar,
mixins: [reactiveChartMixin],
props: {
labels: {
type: [Object, Array],
description: 'Chart labels. This is overridden when `data` is provided'
},
datasets: {
type: [Object, Array],
description: 'Chart datasets. This is overridden when `data` is provided'
},
data: {
type: [Object, Array],
description: 'Chart.js chart data (overrides all default data)'
},
color: {
type: String,
description: 'Chart color. This is overridden when `data` is provided'
},
extraOptions: {
type: Object,
description: 'Chart.js options'
},
title: {
type: String,
description: 'Chart title'
},
},
methods: {
assignChartData() {
let { gradientFill } = this.assignChartOptions(defaultOptions);
let color = this.color || this.fallBackColor;
return {
labels: this.labels || [],
datasets: this.datasets ? this.datasets : [{
label: this.title || '',
backgroundColor: gradientFill,
borderColor: color,
pointBorderColor: "#FFF",
pointBackgroundColor: color,
pointBorderWidth: 2,
pointHoverRadius: 4,
pointHoverBorderWidth: 1,
pointRadius: 4,
fill: true,
borderWidth: 1,
data: this.data || []
}]
}
},
assignChartOptions(initialConfig) {
let color = this.color || this.fallBackColor;
const ctx = document.getElementById(this.chartId).getContext('2d');
const gradientFill = ctx.createLinearGradient(0, 170, 0, 50);
gradientFill.addColorStop(0, "rgba(128, 182, 244, 0)");
gradientFill.addColorStop(1, hexToRGB(color, 0.6));
let extraOptions = this.extraOptions || {}
return {
...initialConfig,
...extraOptions,
gradientFill
};
}
},
mounted() {
this.chartData = this.assignChartData({});
this.options = this.assignChartOptions(defaultOptions);
this.renderChart(this.chartData, this.options, this.extraOptions);
}
}
The bar chart from the above JavaScript file is imported into a Vue component shown below. Whenever there are changes in the form input, the chart needs to be re-rendered. By toggling the boolean loaded variable to false within the onInputChange() method, followed by calling the loadData() function, the chart refreshes. In the loadData() method, an axios request fetches the required data along with the maximum Y-axis value.
After receiving a response, the updateChart() function is triggered to update the chart's data and maximum value. Subsequently, setting loaded back to true ensures a proper visualization of the chart without any sudden disappearance. However, the challenge lies in preventing the brief disappearance of the chart upon updating the Y-axis max value.
To address this issue, a computed property might offer a solution, although the functioning of which requires further understanding. Below is the component code excluding the form fields.
The main goal is to dynamically adjust the max value on the Y-axis without entirely refreshing the chart.
<template>
<div>
<BarChart v-if="loaded" :labels="chartLabels"
:datasets="datasets"
:height="100"
:extraOptions="extraOptions"
>
</BarChart>
<br>
</div>
</template>
<script>
import BarChart from '../../components/Library/UIComponents/Charts/BarChart'
import Dropdown from "../../components/Library/UIComponents/Dropdown"
import GroupedMultiSelectWidget from "~/components/widgets/GroupedMultiSelectWidget"
import SelectWidget from "../../components/widgets/SelectWidget";
export default{
name: 'PopularChart',
components: {BarChart, Dropdown, SelectWidget, GroupedMultiSelectWidget},
data(){
return {
loaded:true,
form:{
day: 'Today',
workspace:'',
machine_family: [],
duration: [],
user_group: [],
dt_start:'',
dt_end:''
},
url: `/api/data_app/job_count_by_hour/`,
chart_data: [],
days: [ {day:"Today", id:"Today"},
{day:"Monday", id:"0"},
{day:"Tuesday",id:"1"},
{day:"Wednesday",id:"2"},
{day:"Thursday",id:"3"},
{day:"Friday",id:"4"},
{day:"Saturday",id:"5"},
{day:"sunday",id:"6"} ],
chartLabels: ["00u", "1u", "2u", "3u","4u","5u", "6u", "7u", "8u", "9u", "10u", "11u", "12u", "13u", "14u", "15u","16u", "17", "18u","19u","20u","21u","22u","23u"],
datasets: [],
maximumValue: '',
extraOptions:{}
}
},
methods: {
onInputChange() {
this.loaded = false
this.loadData()
},
async loadData() {
await this.$axios.get(`${this.url}?day=${this.form.day}&date_start=${this.form.dt_start}&date_end=${this.form.dt_end}&workspace=${this.form.workspace}&user_group=${this.form.user_group}&machine_family=${this.form.machine_family}`)
.then(response => {
this.updateChart(response.data.results,response.data.maximum)
this.loaded = true
})
},
updateChart(data,maxValue) {
this.datasets = [{
label: ["jobs %"],
backgroundColor:"#f93232",
data: data
},]
this.maximumValue = maxValue
this.extraOptions = {
tooltips: {
callbacks:{
label: function (tooltipItems,){
if (tooltipItems.value > ((50/100) * maxValue)){
return 'busy';
}else if (tooltipItems.value < ((30/ 100) * maxValue) ){
return ' not busy';
}else if ( tooltipItems.value < ((40/ 100) * maxValue )){
return 'kind of busy'
}
}
}
},
scales: {
yAxes: [{
gridLines: {
zeroLineColor: "transparent",
display: false,
drawBorder: false,
},
ticks: {
max: this.maximumValue,
display: true,
}
}],
xAxes: [{
gridLines: {
zeroLineColor: "transparent",
display: false,
drawBorder: false,
},
}],
},
}
},
},
mounted() {
this.loadData()
},
}
</script>