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Parenthesize export assignments if needed (microsoft#19590)
* parenthesize export assignments if needed * Add default-specific parenthesization to handle lookahead * New parenthesization logic for export default * Handle commalist and comma cases
1 parent a89c055 commit c2aa13d

11 files changed

+350
-3
lines changed

‎src/compiler/factory.ts

Lines changed: 22 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1982,7 +1982,7 @@ namespace ts {
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node.decorators = asNodeArray(decorators);
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node.modifiers = asNodeArray(modifiers);
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node.isExportEquals = isExportEquals;
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node.expression = expression;
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node.expression = isExportEquals ? parenthesizeBinaryOperand(SyntaxKind.EqualsToken, expression, /*isLeftSideOfBinary*/ false, /*leftOperand*/ undefined) : parenthesizeDefaultExpression(expression);
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return node;
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}
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@@ -3885,6 +3885,27 @@ namespace ts {
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: e;
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}
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/**
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* [Per the spec](https://tc39.github.io/ecma262/#prod-ExportDeclaration), `export default` accepts _AssigmentExpression_ but
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* has a lookahead restriction for `function`, `async function`, and `class`.
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*
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* Basically, that means we need to parenthesize in the following cases:
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*
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* - BinaryExpression of CommaToken
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* - CommaList (synthetic list of multiple comma expressions)
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* - FunctionExpression
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* - ClassExpression
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*/
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export function parenthesizeDefaultExpression(e: Expression) {
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const check = skipPartiallyEmittedExpressions(e);
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return (check.kind === SyntaxKind.ClassExpression ||
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check.kind === SyntaxKind.FunctionExpression ||
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check.kind === SyntaxKind.CommaListExpression ||
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isBinaryExpression(check) && check.operatorToken.kind === SyntaxKind.CommaToken)
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? createParen(e)
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: e;
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}
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/**
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* Wraps an expression in parentheses if it is needed in order to use the expression
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* as the expression of a NewExpression node.

‎tests/baselines/reference/exportDefaultParenthesize.js

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@@ -0,0 +1,72 @@
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//// [tests/cases/compiler/exportDefaultParenthesize.ts] ////
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//// [commalist.ts]
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export default {
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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};
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//// [comma.ts]
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export default {
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['foo']: 42
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};
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//// [functionexpression.ts]
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export default () => 42;
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//// [commalist.js]
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export default (_a = {},
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a['foo' + ''] = 42,
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_a);
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var _a;
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//// [comma.js]
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export default (_a = {},
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_a['foo'] = 42,
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_a);
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var _a;
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//// [functionexpression.js]
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export default (function () { return 42; });

‎tests/baselines/reference/exportDefaultParenthesize.symbols

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@@ -0,0 +1,38 @@
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=== tests/cases/compiler/commalist.ts ===
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export default {
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code. ['foo'+'']: 42,
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No type information for this code.};
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No type information for this code.
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No type information for this code.=== tests/cases/compiler/comma.ts ===
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export default {
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['foo']: 42
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>'foo' : Symbol(['foo'], Decl(comma.ts, 0, 16))
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};
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=== tests/cases/compiler/functionexpression.ts ===
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export default () => 42;
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No type information for this code.
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No type information for this code.

‎tests/baselines/reference/exportDefaultParenthesize.types

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@@ -0,0 +1,159 @@
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=== tests/cases/compiler/commalist.ts ===
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export default {
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>{ ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42, ['foo'+'']: 42,} : { [x: string]: number; }
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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['foo'+'']: 42,
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>'foo'+'' : string
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>'foo' : "foo"
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>'' : ""
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>42 : 42
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};
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=== tests/cases/compiler/comma.ts ===
146+
export default {
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>{ ['foo']: 42} : { ['foo']: number; }
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['foo']: 42
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>'foo' : "foo"
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>42 : 42
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};
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=== tests/cases/compiler/functionexpression.ts ===
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export default () => 42;
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>() => 42 : () => number
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>42 : 42
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‎tests/baselines/reference/exportDefaultParenthesizeES6.js

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//// [classexpr.ts]
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export default (class Foo {} as any);
3+
4+
//// [classexpr.js]
5+
export default (class Foo {
6+
});

‎tests/baselines/reference/exportDefaultParenthesizeES6.symbols

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=== tests/cases/compiler/classexpr.ts ===
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export default (class Foo {} as any);
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>Foo : Symbol(Foo, Decl(classexpr.ts, 0, 16))
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‎tests/baselines/reference/exportDefaultParenthesizeES6.types

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=== tests/cases/compiler/classexpr.ts ===
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export default (class Foo {} as any);
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>(class Foo {} as any) : any
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>class Foo {} as any : any
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>class Foo {} : typeof Foo
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>Foo : typeof Foo
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‎tests/baselines/reference/exportEqualsAmd.js

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@@ -5,5 +5,5 @@ export = { ["hi"]: "there" };
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define(["require", "exports"], function (require, exports) {
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"use strict";
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var _a;
8-
return _a = {}, _a["hi"] = "there", _a;
8+
return (_a = {}, _a["hi"] = "there", _a);
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});

‎tests/baselines/reference/exportEqualsUmd.js

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@@ -13,5 +13,5 @@ export = { ["hi"]: "there" };
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})(function (require, exports) {
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"use strict";
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var _a;
16-
return _a = {}, _a["hi"] = "there", _a;
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return (_a = {}, _a["hi"] = "there", _a);
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});

‎tests/cases/compiler/exportDefaultParenthesize.ts

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// @target: es5
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// @module: esnext
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// @filename: commalist.ts
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export default {
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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['foo'+'']: 42,
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};
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// @filename: comma.ts
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export default {
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['foo']: 42
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};
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// @filename: functionexpression.ts
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export default () => 42;

‎tests/cases/compiler/exportDefaultParenthesizeES6.ts

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// @target: es6
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// @module: esnext
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// @filename: classexpr.ts
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export default (class Foo {} as any);

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