a few things:

- the data is flat arrays of numbers

- there is no per-datapoint memory allocation beyond whatever is necessary for the browser to construct the canvas Path2D object. this keeps the memory pressure low and the GC nearly silent.

- the amount of draw commands is reduced by accumulating the min/max data values per pixel

- uPlot does not generate axis ticks by walking the data. it only uses min/max of the x and y ranges and finds the divisions from that.

- there is no mass-creation of Date objects, data is kept in timestamp format except when hovered.

- the date/time formatting is done by pre-compiling templates and not re-parsing them all the time.

- the cursor interaction uses a binary search over the x array