simple-lazy-jest.js

const lazy = function(name, func) {
  let cached = null;
  afterEach(function() {
    delete global[`$${name}`];
    cached = undefined;
  });

  Object.defineProperty(global, `$${name}`, {
    configurable: true,
    get() {
      if (cached) {
        return cached;
      }
      cached = func();

      return cached;
    },
  });
};