我认为错误来自我调用一个空对象或类似的东西?
代码如下
import React from 'react';
export default class ChartGraph extends React.Component {
componentDidMount() {
let chartCanvas = this.refs.chart;
let data = this.props.data ? this.props.data : "not vailable data";
let chartInstance = new Chart(chartCanvas, { // <= [BUG]: Offending line
type: 'line',
data: {data},
options: {
title: {
display: true,
text: 'My awesome chart'
}
}
});
this.setState({ chart: chartInstance })
}
componentDidUpdate() {
let chart = this.state.chart;
let data = this.props.data;
data.datasets.forEach((dataset, i) => chart.data.datasets[i].data = dataset.data);
chart.data.labels = data.labels;
chart.udpate();
}
render() {
let cssClassName = this.props.className;
const chartStyle = {
width: 600,
height: 250,
color: 'white'
};
return (
<canvas
ref={'chart'}
style={chartStyle}>
</canvas>
);
}
}
错误:
chartgraph.jsx:68Uncaught ReferenceError: Chart is not definedcomponentDidMount @ chartgraph.jsx:68invokeComponentDidMountWithTimer @ ReactCompositeComponent.js:54notifyAll @ CallbackQueue.js:67close @ ReactReconcileTransaction.js:81closeAll @ Transaction.js:204perform @ Transaction.js:151batchedMountComponentIntoNode @ ReactMount.js:126perform @ Transaction.js:138batchedUpdates @ ReactDefaultBatchingStrategy.js:63batchedUpdates @ ReactUpdates.js:98_renderNewRootComponent @ ReactMount.js:285_renderSubtreeIntoContainer @ ReactMount.js:371render @ ReactMount.js:392(anonymous function) @ index.js:11maybeReady @ startup_client.js:26loadingCompleted @ startup_client.js:38
debug.js:41 Exception from Tracker recompute function:
debug.js:41 TypeError: Cannot read property 'chart' of null
at ChartGraph.componentDidUpdate (chartgraph.jsx:83)
at ReactCompositeComponentWrapper.invokeComponentDidUpdateWithTimer (ReactCompositeComponent.js:65)
at CallbackQueue.notifyAll (CallbackQueue.js:67)
at ReactReconcileTransaction.close (ReactReconcileTransaction.js:81)
at ReactReconcileTransaction.closeAll (Transaction.js:204)
at ReactReconcileTransaction.perform (Transaction.js:151)
at ReactUpdatesFlushTransaction.perform (Transaction.js:138)
at ReactUpdatesFlushTransaction.perform (ReactUpdates.js:90)
at Object.flushBatchedUpdates (ReactUpdates.js:173)
at ReactDefaultBatchingStrategyTransaction.closeAll (Transaction.js:204)