1.js

let x = 0;

async function test() {
  x += await 2;
  console.log(x);
}

test();
x += 1;
console.log(x);

2.js

let x = 0;

async function test() {
  x = x + await 2;
  console.log(x);
}

test();
x += 1;
console.log(x);

3.js

let x = 0;

function test() {
  Promise.resolve(2).then((i) => {
    x += i;
  })
  console.log(x);
}

test();
x += 1;
console.log(x);

4.js

let x = 0;

function test() {
  Promise.resolve(2).then((i) => {
    x += i;
    console.log(x);
  })
}

test();
x += 1;
console.log(x);

5.js

let x = 0;

function test() {
  return Promise.resolve(2).then((i) => {
    x += i;
    console.log(x);
  })
}

Promise.resolve(test()).then(() => {
  x += 1;
  console.log(x);
});

results.md

➜ node 1.js # original
1
2
➜ node 2.js # Not using += (I know, silly)
1
2
➜ node 3.js # Ditching async and using Promise.resolve instead of await
0
1
➜ node 4.js # Same as 3 but include console.log in then
1
3
➜ node 5.js # Same as 4 but resolve result from test() call before x += 1
2
3