diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /js/src/tests/non262/lexical-environment/unscopables-mutation.js | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'js/src/tests/non262/lexical-environment/unscopables-mutation.js')
-rw-r--r-- | js/src/tests/non262/lexical-environment/unscopables-mutation.js | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/js/src/tests/non262/lexical-environment/unscopables-mutation.js b/js/src/tests/non262/lexical-environment/unscopables-mutation.js new file mode 100644 index 0000000000..2f35e1dd3c --- /dev/null +++ b/js/src/tests/non262/lexical-environment/unscopables-mutation.js @@ -0,0 +1,44 @@ +// When obj[@@unscopables].x changes, bindings appear and disappear accordingly. + +let x = "global"; +function getX() { return x; } + +let unscopables = {x: true}; +let obj = {x: "obj", [Symbol.unscopables]: unscopables}; + +with (obj) { + assertEq(x, "global"); + x = "global-1"; + assertEq(x, "global-1"); + assertEq(obj.x, "obj"); + + unscopables.x = false; // suddenly x appears in the with-environment + + assertEq(x, "obj"); + x = "obj-1"; + assertEq(getX(), "global-1"); // unchanged + assertEq(obj.x, "obj-1"); + + unscopables.x = true; // *poof* + + assertEq(x, "global-1"); + x = "global-2"; + assertEq(getX(), "global-2"); + assertEq(obj.x, "obj-1"); // unchanged + + // The determination of which binding is assigned happens when the LHS of + // assignment is evaluated, before the RHS. This is observable if we make + // the binding appear or disappear during evaluation of the RHS, before + // assigning. + x = (unscopables.x = false, "global-3"); + assertEq(getX(), "global-3"); + assertEq(obj.x, "obj-1"); + + x = (unscopables.x = true, "obj-2"); + assertEq(getX(), "global-3"); + assertEq(obj.x, "obj-2"); +} + +assertEq(x, "global-3"); + +reportCompare(0, 0); |