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June 7, 2020 05:07
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Pause on exception, with catch, async version
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| function sleep(ms) { | |
| return new Promise((resolve) => setTimeout(resolve, ms)) | |
| } | |
| async function err() { | |
| await sleep(200) | |
| // debugger: pause on uncaught exception | |
| // should pause on this | |
| throw new Error("wow") | |
| } | |
| function err2() { | |
| throw new Error("sync") | |
| } | |
| // How to implement this "exec" function?? | |
| // React version only works for the sync call stack (IIRC) | |
| // https://github.com/facebook/react/blob/4c7036e807fa18a3e21a5182983c7c0f05c5936e/packages/shared/invokeGuardedCallbackImpl.js#L31 | |
| async function exec(f) { | |
| return await f() | |
| } | |
| exec(err).catch((x) => console.warn(x.message)) // wow | |
| exec(err2).catch((x) => console.warn(x.message)) // sync |
Another solution, pollute the call stack by dynamic named function. (But chrome only give 10 lines of call stack so it will be useless).
Therefore in the unhandledrejection I can check if the error call stack have the secret I set to know if it is my function.
Ok, I resolved it. The solution is too cursed and I'm happy to find a better solution
<body></body>
<script>
function exec(f) {
return new Promise((resolve, reject) => {
async function wrappedF() {
resolve(await f())
}
var i = document.createElement("iframe")
window.addEventListener("unhandledrejection", (e) =>
console.log(`From main realm ${e.reason?.message}`)
)
i.onload = () => {
const document = i.contentDocument
const window = i.contentWindow
const button = document.createElement("button")
document.body.appendChild(button)
i.contentWindow.f = mainWorldTask
button.onclick = () => {
new window.Promise((r) => {
wrappedF().then(r)
})
}
window.addEventListener("unhandledrejection", (e) =>
reject(e.reason)
)
setTimeout(() => {
button.click()
}, 500)
}
document.body.appendChild(i)
})
}
console.log(exec(mainWorldTask).catch((err) => console.log(err)))
console.log(exec(ok))
function sleep(ms) {
return new Promise((resolve) => setTimeout(resolve, ms))
}
async function mainWorldTask() {
console.log("hi")
await sleep(200)
throw new Error("err msg")
}
async function ok() {
return 123
}
</script>
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I get the answer. create a new iframe each time, let the callback run in that realm.
so the unhandledrejection in that realm must come from my code (if there is no user script / web extension).