3👍
I think you have a TSLint error there, rather than a TypeScript error.
It wants you to change:
label: function(tooltipItem, dataChartTemperature) {
To:
label: (tooltipItem, dataChartTemperature) => {
This would only impact you if there is some scoped item in there that could be lost by a change of context, but I guess TSLint hearts arrow functions.
This is the TSLint object-shorthand rule I think you are triggering, along with how to change it if you want to.
Source:stackexchange.com