README.md

Smart Mock

Yet another proxy mock (YAPM?). Still in a very early state (EXPECT BUGS!).

A mock that records operations for code generation later. The idea is somewhat similar to prepack, but instead of interpreting code by other JS code, we run it in a JS VM and later use the mock to repeat the same operations. Ideally combined with a terser-like optimizer. Please check the example in pkgbld to see how it is used to eject config.

Changelog

API

default () => { createMock, generateGlobals, generate }

The default export function is a factory that creates 3 other functions with shared state.

createMock<T extends object>(object: T, name: string): T

Function to create a mock wrapper around an object and define a global name for later usage. object can be a real original object or a pure mock object with the same behavior for the specific situation. All operations on this object will be recorded by the mock.

generate(object: unknown): string

Function to generate code for some export point (exit point). It will try to automatically inline operations that can be inlined.

generateGlobals(): string

Function to generate global code that cannot be inlined to an exit point.

Example

import createMockProvider from "@slimlib/smart-mock";
const { createMock, generate, generateGlobals } = createMockProvider();
const mock = createMock(
  {
    fly() {
      return { status: "flying" };
    },
    land() {},
    name: "",
  },
  "fly"
);
mock.name = "Moth";
const status = mock.fly();
mock.land();

At this point generate(mock) will result in mock, generate(mock.name) in 'Moth' and generate(status) in fly.fly(). And if you afterwards call generateGlobals() you get something like:

fly.name = "Moth";
const tmp_0 = fly.land;
tmp_0();

Each generate call updates counters / flags in the mock so generateGlobals only emits what was not generated at the time of the call.

License

MIT