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Destructuring assignment removes undefined from type when default value is given

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Nathan Shively-Sanders
2016-06-29 09:12:50 -07:00
parent 6be7d9caa6
commit c5e680c8be
5 changed files with 50 additions and 0 deletions
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6
src/compiler/checker.ts
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@@ -12544,6 +12544,12 @@ namespace ts {
if (exprOrAssignment.kind === SyntaxKind.ShorthandPropertyAssignment) {
const prop = <ShorthandPropertyAssignment>exprOrAssignment;
if (prop.objectAssignmentInitializer) {
// In strict null checking mode, if a default value of a non-undefined type is specified, remove
// undefined from the final type.
if (strictNullChecks &&
!(getCombinedTypeFlags(checkExpressionCached(prop.objectAssignmentInitializer)) & TypeFlags.Undefined)) {
sourceType = getTypeWithFacts(sourceType, TypeFacts.NEUndefined);
}
checkBinaryLikeExpression(prop.name, prop.equalsToken, prop.objectAssignmentInitializer, contextualMapper);
}
target = (<ShorthandPropertyAssignment>exprOrAssignment).name;