In a pot over high heat, bring 1½ cups salted water to a boil. Add the rice, reduce to a simmer, cover and cook until the liquid is absorbed and rice is tender, 20 to 25 minutes.
While the rice cooks, prepare the vegetables and shrimp.

• Cut the bok choy in half, lengthwise.
• Peel and thinly slice the shallot.
• Cut the serrano chile in half lengthwise and then into thin diagonal slices.
• Coarsely chop the garlic.
• Core and remove the seeds from the red pepper; cut lengthwise into ¼-inch pieces.
• Cut the lemongrass on an angle into 2-inch long pieces.
• Cut off the tough outer layer of the pineapple, then the fruit into quarters, remove the core and cut the pineapple into ¼-inch thick pieces.
• Rinse the shrimp and pat dry.
• Pick the basil leaves from the stems and coarsely chop. Discard the stems.

In a pan over medium heat, warm 1 to 2 tablespoons oil until hot but not smoking. Add the bok choy cut-side down and cook until browned and just tender-crisp, 2 to 3 minutes on each side. Transfer the bok choy to a plate.
Add the shallots, chile, and lemongrass. Season with salt and cook until the shallots are softened, 1 to 2 minutes. Add the garlic and red peppers and cook, stirring occasionally, until peppers start to soften, 2 to 3 minutes. Add the pineapple and cook, tossing occasionally, until heated through, 1 to 2 minutes.
Add the shrimp and the stir-fry sauce and cook, stirring occasionally until the shrimp is pink and cooked through, 4 to 5 minutes. Remove from the heat and add the basil.

Transfer the rice and stir-fry to individual plates or bowls, arrange the bok choy on the side and serve.