← back to v143 · upsert

conformance · v143

v143 · upsert — conformance probe

7 assertions drawn from the spec. Each is a single contract the spec text makes. Pass/fail reflects what this browser executed; blocked means the contract was not run because it needs user mediation, hardware, or another unavailable precondition. Open the page in Chrome stable / canary / Firefox / Safari to compare.

browser: spec: https://github.com/tc39/proposal-upsert chromestatus: #5201653661827072 generated 2026-06-01T11:15:00Z by conformance-author-v1-subagent
0
pass
0
fail
0
blocked
7
total
id contract kind verdict detail
map-getorinsert-is-function Map.prototype.getOrInsert is exposed as a function. spec ↗ typeof
map-getorinsertcomputed-is-function Map.prototype.getOrInsertComputed is exposed as a function. spec ↗ typeof
map-getorinsert-inserts-when-missing getOrInsert sets and returns the default when the key is absent. spec ↗ script
map-getorinsert-keeps-existing getOrInsert returns the existing value and does not overwrite when the key is present. spec ↗ script
map-getorinsertcomputed-lazy getOrInsertComputed only invokes the callback when the key is absent. spec ↗ script
weakmap-getorinsert-is-function WeakMap.prototype.getOrInsert is also exposed (same proposal). spec ↗ typeof
weakmap-getorinsertcomputed-is-function WeakMap.prototype.getOrInsertComputed is exposed. spec ↗ typeof