microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-05-27 04:46:25 -05:00
Code Issues Packages Projects Releases 212 Wiki Activity

Initial implementation of conditional type operator

Browse Source
This commit is contained in:
Anders Hejlsberg
2017-12-05 14:18:11 -08:00
parent 334bf4eaf7
commit 57ca7680c9
10 changed files with 165 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/compiler/parser.ts
View File

@@ -147,6 +147,11 @@ namespace ts {
case SyntaxKind.UnionType:
case SyntaxKind.IntersectionType:
return visitNodes(cbNode, cbNodes, (<UnionOrIntersectionTypeNode>node).types);
case SyntaxKind.ConditionalType:
return visitNode(cbNode, (<ConditionalTypeNode>node).checkType) ||
visitNode(cbNode, (<ConditionalTypeNode>node).extendsType) ||
visitNode(cbNode, (<ConditionalTypeNode>node).trueType) ||
visitNode(cbNode, (<ConditionalTypeNode>node).falseType);
case SyntaxKind.ParenthesizedType:
case SyntaxKind.TypeOperator:
return visitNode(cbNode, (<ParenthesizedTypeNode | TypeOperatorNode>node).type);
@@ -2760,6 +2765,10 @@ namespace ts {
type = createJSDocPostfixType(SyntaxKind.JSDocNonNullableType, type);
break;
case SyntaxKind.QuestionToken:
// only parse postfix ? inside jsdoc, otherwise it is a conditional type
if (!(contextFlags & NodeFlags.JSDoc)) {
return type;
}
type = createJSDocPostfixType(SyntaxKind.JSDocNullableType, type);
break;
case SyntaxKind.OpenBracketToken:
@@ -2839,6 +2848,21 @@ namespace ts {
return parseUnionOrIntersectionType(SyntaxKind.UnionType, parseIntersectionTypeOrHigher, SyntaxKind.BarToken);
}
function parseConditionalTypeOrHigher(): TypeNode {
const type = parseUnionTypeOrHigher();
if (parseOptional(SyntaxKind.ExtendsKeyword)) {
const node = <ConditionalTypeNode>createNode(SyntaxKind.ConditionalType, type.pos);
node.checkType = type;
node.extendsType = parseUnionTypeOrHigher();
parseExpected(SyntaxKind.QuestionToken);
node.trueType = parseConditionalTypeOrHigher();
parseExpected(SyntaxKind.ColonToken);
node.falseType = parseConditionalTypeOrHigher();
return finishNode(node);
}
return type;
}
function isStartOfFunctionType(): boolean {
if (token() === SyntaxKind.LessThanToken) {
return true;
@@ -2928,7 +2952,7 @@ namespace ts {
if (token() === SyntaxKind.NewKeyword) {
return parseFunctionOrConstructorType(SyntaxKind.ConstructorType);
}
return parseUnionTypeOrHigher();
return parseConditionalTypeOrHigher();
}
function parseTypeAnnotation(): TypeNode {