plot_pseudotime_heatmap() function has been deleted from monocle3. As a result, this is a example script of how to create a heatmap of these trajectory genes along with pseudotime information from cds object created from monocle3 using Complex Heatmap package.
Backbone of this script was modified from jonhsussman's helpful comment here: cole-trapnell-lab/monocle-release#295 which performs a smooth spline function row-wise across all the cells. to include user-defined annotations, clustering based splitting and pseudotime barplot.

Author: Kei Onn, Lai