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Test Info:
/* Any copyright is dedicated to the Public Domain.
// Test that $_ works as expected with top-level await expressions.
"use strict";
requestLongerTimeout(2);
const TEST_URI =
"data:text/html;charset=utf-8,<!DOCTYPE html>top-level await + $_";
add_task(async function () {
// Enable await mapping.
await pushPref("devtools.debugger.features.map-await-expression", true);
const hud = await openNewTabAndConsole(TEST_URI);
info("Evaluate a simple expression to populate $_");
await executeAndWaitForResultMessage(hud, `1 + 1`, `2`);
await executeAndWaitForResultMessage(hud, `$_ + 1`, `3`);
ok(true, "$_ works as expected");
info(
"Check that $_ does not get replaced until the top-level await is resolved"
);
const onAwaitResultMessage = executeAndWaitForResultMessage(
hud,
`await new Promise(res => setTimeout(() => res([1,2,3, $_]), 1000))`,
`Array(4) [ 1, 2, 3, 4 ]`
);
await executeAndWaitForResultMessage(hud, `$_ + 1`, `4`);
ok(true, "$_ was not impacted by the top-level await input");
await onAwaitResultMessage;
ok(true, "the top-level await result can use $_ in its returned value");
await executeAndWaitForResultMessage(
hud,
`await new Promise(res => setTimeout(() => res([...$_, 5]), 1000))`,
`Array(5) [ 1, 2, 3, 4, 5 ]`
);
ok(true, "$_ is assigned with the result of the top-level await");
info("Check that awaiting for a rejecting promise does not re-assign $_");
await executeAndWaitForErrorMessage(
hud,
`x = await new Promise((resolve,reject) =>
setTimeout(() => reject("await-" + "rej"), 500))`,
`await-rej`
);
await executeAndWaitForResultMessage(hud, `$_`, `Array(5) [ 1, 2, 3, 4, 5 ]`);
ok(true, "$_ wasn't re-assigned");
info("Check that $_ gets the value of the last resolved await expression");
const delays = [2000, 1000, 4000, 3000];
const inputs = delays.map(
delay => `await new Promise(
r => setTimeout(() => r("await-concurrent-" + ${delay}), ${delay}))`
);
// Let's wait for the message that should be displayed last.
const onMessage = waitForMessageByType(
hud,
"await-concurrent-4000",
".result"
);
for (const input of inputs) {
execute(hud, input);
}
await onMessage;
await executeAndWaitForResultMessage(
hud,
`"result: " + $_`,
`"result: await-concurrent-4000"`
);
ok(
true,
"$_ was replaced with the last resolving top-level await evaluation result"
);
});