Parameterizes the bindReporter type on the metric passed in so that the callback can now be typed specifically for that metric (e.g. a result for CLSMetric must be using a CLSReportCallback).
This required initMetric to be parameterized similarly, so the returned metric type is now based on the metric name passed in.
let metric = initMetric('FCP');
// ^ FCPMetric
The main change required was using a union of the metric types wherever the base Metric interface is currently used. This leaves most uses of it unchanged, but allows narrowing to which specific metric is being used based on the name property.
I renamed the existing Metric to be MetricBase and named the union Metric to keep the uses of it unchanged, but if someone has better naming suggestions, changing is no problem :)
Can land after #356
Parameterizes the
bindReportertype on themetricpassed in so that thecallbackcan now be typed specifically for that metric (e.g. a result forCLSMetricmust be using aCLSReportCallback).This required
initMetricto be parameterized similarly, so the returned metric type is now based on the metricnamepassed in.The main change required was using a union of the metric types wherever the base
Metricinterface is currently used. This leaves most uses of it unchanged, but allows narrowing to which specific metric is being used based on thenameproperty.I renamed the existing
Metricto beMetricBaseand named the unionMetricto keep the uses of it unchanged, but if someone has better naming suggestions, changing is no problem :)