Preheat oven to 400 degrees F (200 degrees C). Grease a 9x5-inch loaf pan and line with parchment paper.
Combine flour, baking powder, cinnamon, baking soda, and salt in a bowl. Fold in chopped dates.
Combine bananas, coconut oil, and vanilla extract in a separate bowl. Add Demerara sugar and mash together with a fork. Add flour mixture and quickly mix together with a spatula until batter comes together. Add a few teaspoons of water if the batter seems too dry. Mix well and transfer to the prepared loaf pan.
Bake in the preheated oven until the top has a nice golden color and a skewer into the center comes out clean, 30 to 35 minutes. Remove from oven and allow to cool, about 30 minutes.
Mix confectioners' sugar with water until the glaze has the desired consistency and drizzle over banana bread.