JSFiddle - React, Tailwind, and code Playground

JavaScript

const program = {
    "Day 1": {
      exercise: {
        exerciseType: ["you have no exercises", "please add"],
      },
    },
    "Day 2": {
      exercise: {
        exerciseType: ["push-ups", "crunches"],
      },
    },
  }


    Object.defineProperty(program, 'fire',
        Object.getOwnPropertyDescriptor(program, 'Day 1'));
    delete program['Day 1'];

console.log(program)