[Chartjs]-Chart.js Uncaught TypeError: Cannot read properties of undefined (reading 'options')

chartfour is the name of the chart configuration you’re using for creating your chart. myChart2.chartfour however does not exist.

When creating the chart, make sur to to assign it to a global constant…

const myChart2 = new Chart('myChart2', chartfour);

…then, you can directly access its options and data as follows:

myChart2.options.scales.x.time.unit = period.value;
myChart2.data.datasets[0].data = months;
...