#8926 Add getWithDefault and getOrThrow to Belt.HashMap

Belt.HashMap, Belt.HashMap.Int and Belt.HashMap.String gain getWithDefault and getOrThrow, the same lookups Belt.Map and Belt.MutableMap already have. They walk the bucket directly, so a hit allocates no option; getOrThrow throws Not_found like the other Belt maps.

Example ReScript

let m = Belt.HashMap.Int.fromArray([(1, "a")])m->Belt.HashMap.Int.getWithDefault(2, "z") == "z"m->Belt.HashMap.Int.getOrThrow(1) == "a"

Review

• Why getWithDefault and not getOr, as the issue title says? Belt names this lookup getWithDefault everywhere (Option, Map, MutableMap and their Int/String variants) and has no getOr; the new functions follow Belt. getOrThrow is the name Belt already uses, without a deprecated getExn alias for a new API.

Output

changedtests/belt_tests/src/belt_hashmap_test.mjs (new tests); no existing program compiles differently

Tests

other~ tests/belt_tests/src/belt_hashmap_test.res plus docstring examples in Belt_HashMap.resi, Belt_HashMapInt.resi, Belt_HashMapString.resi

• Changelog fragment changes/belt-hashmap-get-with-default.feature.md
• 1 committed generated JS file changes