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Add numeric constraint to type parameter of mapped types with name type and array constraints (#55774)

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This commit is contained in:
Mateusz Burzyński
2024-01-16 19:59:00 +01:00
committed by GitHub
parent bbef6a7a31
commit 3f8707d04f
17 changed files with 437 additions and 224 deletions
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12
src/compiler/checker.ts
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@@ -13850,6 +13850,14 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}
function forEachMappedTypePropertyKeyTypeAndIndexSignatureKeyType(type: Type, include: TypeFlags, stringsOnly: boolean, cb: (keyType: Type) => void) {
if (isTupleType(type)) {
forEachType(getUnionType(getElementTypes(type).map((_, i) => getStringLiteralType("" + i))), cb);
return;
}
if (isArrayType(type)) {
cb(numberType);
return;
}
for (const prop of getPropertiesOfType(type)) {
cb(getLiteralTypeFromProperty(prop, include));
}
@@ -16242,8 +16250,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}
}
// Given a homomorphic mapped type { [K in keyof T]: XXX }, where T is constrained to an array or tuple type, in the
// template type XXX, K has an added constraint of number | `${number}`.
else if (type.flags & TypeFlags.TypeParameter && parent.kind === SyntaxKind.MappedType && node === (parent as MappedTypeNode).type) {
// template type XXX, K has an added constraint of number | `${number}`. The same is added in the optional name type.
else if (type.flags & TypeFlags.TypeParameter && parent.kind === SyntaxKind.MappedType && (node === (parent as MappedTypeNode).type || node === (parent as MappedTypeNode).nameType)) {
const mappedType = getTypeFromTypeNode(parent as TypeNode) as MappedType;
if (getTypeParameterFromMappedType(mappedType) === getActualTypeVariable(type)) {
const typeParameter = getHomomorphicTypeVariable(mappedType);