A primitive

count-to-five-a.js

import { call, variable, wait } from '@microstates/effects';

function* countToFive() {
  let count = variable(1);
  this.call(count, function*() { // the count variable is now the context of all operations
    this.when(() => count.get() <= 5, function*() { // guard sees value of `count`
      console.log(`count is ${count.get()}`);
      yield wait(1000)
      yield count.update(c => c + 1)
    });
  });
}

let main = call(countToFive);

// the effects can be closed cleanly at any time.
process.stdin.on('keypress', e => {
  if (e.isCtrl && e.char === 'c') {
    main.close();
  }
})

count-to-five-b.js

import { call, state, wait } from '@microstates/effects';

// we can build on this reactive primitive effect to use
// a microstate instead. The `state` function creates an effect
// variable that is based on microstates. However, it's just a "power up"
// on the underlying mechanism.
function* countToFive() {
  let count = state(Number, 1);
  this.call(count, function*() { // the count variable is now the context of all operations
    this.when(() => count.state <= 5, function*() { // guard sees value of `count`
      console.log(`count is ${count.state}`);
      yield wait(1000)
      yield count.increment();
    });
  });
}

let main = call(countToFive);

process.stdin.on('keypress', e => {
  if (e.isCtrl && e.char === 'c') {
    main.close();
  }
})

count-to-five-c.js

import { call, state, wait } from '@microstates/effects';

// finally, you can pass in a variable to your generator function.
function* countTo(count) {
  this.when(() => count.state <= 5, function*() { // guard sees value of `count`
    console.log(`count is ${count.state}`);
    yield wait(1000)
    yield count.increment();
  });
}

let main = call(countTo, state(Number, 1));

process.stdin.on('keypress', e => {
  if (e.isCtrl && e.char === 'c') {
    main.close();
  }
})