README.md

Generate Broken CommonJS Code

Microbundle generates broken CommonJS code when compiling from Typescript. The continue keyword in the compiled JS is not respected. The problem is caused by the usage of async/await within the while loop. Commenting out: await new Promise((resolve) => setTimeout(resolve, 100)); produces the expected result.

Input - index.ts

async function brokenContinue() {
  let j = 0;

  while (j <= 3) {
    j++;
    console.log("AT THE TOP");

    if (j === 1) {
      console.log("\t- j === 1");
      console.log("\t- waiting for 100ms");
      await new Promise((resolve) => setTimeout(resolve, 100));
      console.log('\t- continue, next log will be "AT THE TOP"');
      continue;
    }

    console.log("AT THE BOTTOM");
  }
}

void brokenContinue();

Output - dist/index.cjs

$ node dist/index.cjs
AT THE TOP
	- j === 1
	- waiting for 100ms
	- continue, next log will be "AT THE TOP"
AT THE BOTTOM   <--------- This should be "AT THE TOP"
AT THE TOP
AT THE BOTTOM
AT THE TOP
AT THE BOTTOM
AT THE TOP
AT THE BOTTOM

Notes:

• Compiling using tsc generates JS that works correctly.
• Compiling to modern JS (with microbundle) generates code that works correctly.