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Improve perf of unions with many primitives (#45220)

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This commit is contained in:
Yuya Tanaka
2021-10-13 08:07:21 +09:00
committed by GitHub
parent 44deb84460
commit 9e2fc16c32
1 changed files with 3 additions and 2 deletions
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5
src/compiler/checker.ts
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@@ -22652,8 +22652,9 @@ namespace ts {
// constituent types keyed by the literal types of the property by that name in each constituent type.
function getKeyPropertyName(unionType: UnionType): __String | undefined {
const types = unionType.types;
// We only construct maps for large unions with non-primitive constituents.
if (types.length < 10 || getObjectFlags(unionType) & ObjectFlags.PrimitiveUnion) {
// We only construct maps for unions with many non-primitive constituents.
if (types.length < 10 || getObjectFlags(unionType) & ObjectFlags.PrimitiveUnion ||
countWhere(types, t => !!(t.flags & (TypeFlags.Object | TypeFlags.InstantiableNonPrimitive))) < 10) {
return undefined;
}
if (unionType.keyPropertyName === undefined) {