Microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2025-11-18 17:21:48 +00:00
Code Issues Packages Projects Releases Wiki Activity

When binding pattern contextually types x || y, x contextually types y

Browse Source
This commit is contained in:
Anders Hejlsberg
2019-05-31 16:40:22 -07:00
parent 487bd78ecc
commit 4fc5f6a5ff
1 changed files with 6 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/compiler/checker.ts
+6 -4
View File
@@ -18435,11 +18435,13 @@ namespace ts {
}
return contextSensitive === true ? getTypeOfExpression(left) : contextSensitive;
case SyntaxKind.BarBarToken:
// When an || expression has a contextual type, the operands are contextually typed by that type. When an ||
// expression has no contextual type, the right operand is contextually typed by the type of the left operand,
// except for the special case of Javascript declarations of the form `namespace.prop = namespace.prop || {}`
// When an || expression has a contextual type, the operands are contextually typed by that type, except
// when that type originates in a binding pattern, the right operand is contextually typed by the type of
// the left operand. When an || expression has no contextual type, the right operand is contextually typed
// by the type of the left operand, except for the special case of Javascript declarations of the form
// `namespace.prop = namespace.prop || {}`.
const type = getContextualType(binaryExpression, contextFlags);
return !type && node === right && !isDefaultedExpandoInitializer(binaryExpression) ?
return node === right && (type && type.pattern || !type && !isDefaultedExpandoInitializer(binaryExpression)) ?
getTypeOfExpression(left) : type;
case SyntaxKind.AmpersandAmpersandToken:
case SyntaxKind.CommaToken: