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Commit 9c40d27

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weswighamweswigham
authored
Downlevel destructuring in module transformer if destructured variable has multiple names (microsoft#23832)
* Downlevel destructuring in module transformer if destructured variable has multiple names * Alter indentation
1 parent b5b7fc4 commit 9c40d27
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5 files changed

+321-19Lines changed: 321 additions & 19 deletions

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‎src/compiler/transformers/module/module.ts‎

Copy file name to clipboardExpand all lines: src/compiler/transformers/module/module.ts
+90-19Lines changed: 90 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -451,7 +451,7 @@ namespace ts {
451451
*/
452452
function addExportEqualsIfNeeded(statements: Statement[], emitAsReturn: boolean) {
453453
if (currentModuleInfo.exportEquals) {
454-
const expressionResult = visitNode(currentModuleInfo.exportEquals.expression, importCallExpressionVisitor);
454+
const expressionResult = visitNode(currentModuleInfo.exportEquals.expression, moduleExpressionElementVisitor);
455455
if (expressionResult) {
456456
if (emitAsReturn) {
457457
const statement = createReturn(expressionResult);
@@ -517,27 +517,82 @@ namespace ts {
517517
return visitEndOfDeclarationMarker(<EndOfDeclarationMarker>node);
518518

519519
default:
520-
return visitEachChild(node, importCallExpressionVisitor, context);
520+
return visitEachChild(node, moduleExpressionElementVisitor, context);
521521
}
522522
}
523523

524-
function importCallExpressionVisitor(node: Expression): VisitResult<Expression> {
525-
// This visitor does not need to descend into the tree if there is no dynamic import,
524+
function moduleExpressionElementVisitor(node: Expression): VisitResult<Expression> {
525+
// This visitor does not need to descend into the tree if there is no dynamic import or destructuring assignment,
526526
// as export/import statements are only transformed at the top level of a file.
527-
if (!(node.transformFlags & TransformFlags.ContainsDynamicImport)) {
527+
if (!(node.transformFlags & TransformFlags.ContainsDynamicImport) && !(node.transformFlags & TransformFlags.ContainsDestructuringAssignment)) {
528528
return node;
529529
}
530530

531531
if (isImportCall(node)) {
532532
return visitImportCallExpression(node);
533533
}
534+
else if (node.transformFlags & TransformFlags.DestructuringAssignment && isBinaryExpression(node)) {
535+
return visitDestructuringAssignment(node as DestructuringAssignment);
536+
}
534537
else {
535-
return visitEachChild(node, importCallExpressionVisitor, context);
538+
return visitEachChild(node, moduleExpressionElementVisitor, context);
536539
}
537540
}
538541

542+
function destructuringNeedsFlattening(node: Expression): boolean {
543+
if (isObjectLiteralExpression(node)) {
544+
for (const elem of node.properties) {
545+
switch (elem.kind) {
546+
case SyntaxKind.PropertyAssignment:
547+
if (destructuringNeedsFlattening(elem.initializer)) {
548+
return true;
549+
}
550+
break;
551+
case SyntaxKind.ShorthandPropertyAssignment:
552+
if (destructuringNeedsFlattening(elem.name)) {
553+
return true;
554+
}
555+
break;
556+
case SyntaxKind.SpreadAssignment:
557+
if (destructuringNeedsFlattening(elem.expression)) {
558+
return true;
559+
}
560+
break;
561+
case SyntaxKind.MethodDeclaration:
562+
case SyntaxKind.GetAccessor:
563+
case SyntaxKind.SetAccessor:
564+
return false;
565+
default: Debug.assertNever(elem, "Unhandled object member kind");
566+
}
567+
}
568+
}
569+
else if (isArrayLiteralExpression(node)) {
570+
for (const elem of node.elements) {
571+
if (isSpreadElement(elem)) {
572+
if (destructuringNeedsFlattening(elem.expression)) {
573+
return true;
574+
}
575+
}
576+
else if (destructuringNeedsFlattening(elem)) {
577+
return true;
578+
}
579+
}
580+
}
581+
else if (isIdentifier(node)) {
582+
return length(getExports(node)) > (isExportName(node) ? 1 : 0);
583+
}
584+
return false;
585+
}
586+
587+
function visitDestructuringAssignment(node: DestructuringAssignment): Expression {
588+
if (destructuringNeedsFlattening(node.left)) {
589+
return flattenDestructuringAssignment(node, moduleExpressionElementVisitor, context, FlattenLevel.All, /*needsValue*/ false, createAllExportExpressions);
590+
}
591+
return visitEachChild(node, moduleExpressionElementVisitor, context);
592+
}
593+
539594
function visitImportCallExpression(node: ImportCall): Expression {
540-
const argument = visitNode(firstOrUndefined(node.arguments), importCallExpressionVisitor);
595+
const argument = visitNode(firstOrUndefined(node.arguments), moduleExpressionElementVisitor);
541596
const containsLexicalThis = !!(node.transformFlags & TransformFlags.ContainsLexicalThis);
542597
switch (compilerOptions.module) {
543598
case ModuleKind.AMD:
@@ -959,10 +1014,10 @@ namespace ts {
9591014
if (original && hasAssociatedEndOfDeclarationMarker(original)) {
9601015
// Defer exports until we encounter an EndOfDeclarationMarker node
9611016
const id = getOriginalNodeId(node);
962-
deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), visitNode(node.expression, importCallExpressionVisitor), /*location*/ node, /*allowComments*/ true);
1017+
deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), visitNode(node.expression, moduleExpressionElementVisitor), /*location*/ node, /*allowComments*/ true);
9631018
}
9641019
else {
965-
statements = appendExportStatement(statements, createIdentifier("default"), visitNode(node.expression, importCallExpressionVisitor), /*location*/ node, /*allowComments*/ true);
1020+
statements = appendExportStatement(statements, createIdentifier("default"), visitNode(node.expression, moduleExpressionElementVisitor), /*location*/ node, /*allowComments*/ true);
9661021
}
9671022

9681023
return singleOrMany(statements);
@@ -985,9 +1040,9 @@ namespace ts {
9851040
node.asteriskToken,
9861041
getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
9871042
/*typeParameters*/ undefined,
988-
visitNodes(node.parameters, importCallExpressionVisitor),
1043+
visitNodes(node.parameters, moduleExpressionElementVisitor),
9891044
/*type*/ undefined,
990-
visitEachChild(node.body, importCallExpressionVisitor, context)
1045+
visitEachChild(node.body, moduleExpressionElementVisitor, context)
9911046
),
9921047
/*location*/ node
9931048
),
@@ -996,7 +1051,7 @@ namespace ts {
9961051
);
9971052
}
9981053
else {
999-
statements = append(statements, visitEachChild(node, importCallExpressionVisitor, context));
1054+
statements = append(statements, visitEachChild(node, moduleExpressionElementVisitor, context));
10001055
}
10011056

10021057
if (hasAssociatedEndOfDeclarationMarker(node)) {
@@ -1027,8 +1082,8 @@ namespace ts {
10271082
visitNodes(node.modifiers, modifierVisitor, isModifier),
10281083
getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
10291084
/*typeParameters*/ undefined,
1030-
visitNodes(node.heritageClauses, importCallExpressionVisitor),
1031-
visitNodes(node.members, importCallExpressionVisitor)
1085+
visitNodes(node.heritageClauses, moduleExpressionElementVisitor),
1086+
visitNodes(node.members, moduleExpressionElementVisitor)
10321087
),
10331088
node
10341089
),
@@ -1037,7 +1092,7 @@ namespace ts {
10371092
);
10381093
}
10391094
else {
1040-
statements = append(statements, visitEachChild(node, importCallExpressionVisitor, context));
1095+
statements = append(statements, visitEachChild(node, moduleExpressionElementVisitor, context));
10411096
}
10421097

10431098
if (hasAssociatedEndOfDeclarationMarker(node)) {
@@ -1089,7 +1144,7 @@ namespace ts {
10891144
}
10901145
}
10911146
else {
1092-
statements = append(statements, visitEachChild(node, importCallExpressionVisitor, context));
1147+
statements = append(statements, visitEachChild(node, moduleExpressionElementVisitor, context));
10931148
}
10941149

10951150
if (hasAssociatedEndOfDeclarationMarker(node)) {
@@ -1104,6 +1159,22 @@ namespace ts {
11041159
return singleOrMany(statements);
11051160
}
11061161

1162+
function createAllExportExpressions(name: Identifier, value: Expression, location?: TextRange) {
1163+
const exportedNames = getExports(name);
1164+
if (exportedNames) {
1165+
// For each additional export of the declaration, apply an export assignment.
1166+
let expression: Expression = isExportName(name) ? value : createAssignment(name, value);
1167+
for (const exportName of exportedNames) {
1168+
// Mark the node to prevent triggering substitution.
1169+
setEmitFlags(expression, EmitFlags.NoSubstitution);
1170+
expression = createExportExpression(exportName, expression, /*location*/ location);
1171+
}
1172+
1173+
return expression;
1174+
}
1175+
return createAssignment(name, value);
1176+
}
1177+
11071178
/**
11081179
* Transforms an exported variable with an initializer into an expression.
11091180
*
@@ -1112,12 +1183,12 @@ namespace ts {
11121183
function transformInitializedVariable(node: VariableDeclaration): Expression {
11131184
if (isBindingPattern(node.name)) {
11141185
return flattenDestructuringAssignment(
1115-
visitNode(node, importCallExpressionVisitor),
1186+
visitNode(node, moduleExpressionElementVisitor),
11161187
/*visitor*/ undefined,
11171188
context,
11181189
FlattenLevel.All,
11191190
/*needsValue*/ false,
1120-
createExportExpression
1191+
createAllExportExpressions
11211192
);
11221193
}
11231194
else {
@@ -1129,7 +1200,7 @@ namespace ts {
11291200
),
11301201
/*location*/ node.name
11311202
),
1132-
visitNode(node.initializer, importCallExpressionVisitor)
1203+
visitNode(node.initializer, moduleExpressionElementVisitor)
11331204
);
11341205
}
11351206
}
Collapse file

‎tests/baselines/reference/destructuringAssignmentWithExportedName.js‎

Copy file name to clipboard
+53Lines changed: 53 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,53 @@
1+
//// [destructuringAssignmentWithExportedName.ts]
2+
export let exportedFoo: any;
3+
let nonexportedFoo: any;
4+
5+
// sanity checks
6+
exportedFoo = null;
7+
nonexportedFoo = null;
8+
9+
if (null as any) {
10+
({ exportedFoo, nonexportedFoo } = null as any);
11+
}
12+
else if (null as any) {
13+
({ foo: exportedFoo, bar: nonexportedFoo } = null as any);
14+
}
15+
else if (null as any) {
16+
({ foo: { bar: exportedFoo, baz: nonexportedFoo } } = null as any);
17+
}
18+
else if (null as any) {
19+
([exportedFoo, nonexportedFoo] = null as any);
20+
}
21+
else {
22+
([[exportedFoo, nonexportedFoo]] = null as any);
23+
}
24+
25+
export { nonexportedFoo };
26+
export { exportedFoo as foo, nonexportedFoo as nfoo };
27+
28+
//// [destructuringAssignmentWithExportedName.js]
29+
"use strict";
30+
Object.defineProperty(exports, "__esModule", { value: true });
31+
exports.foo = exports.exportedFoo;
32+
let nonexportedFoo;
33+
exports.nonexportedFoo = nonexportedFoo;
34+
exports.nfoo = nonexportedFoo;
35+
// sanity checks
36+
exports.foo = exports.exportedFoo = null;
37+
exports.nfoo = exports.nonexportedFoo = nonexportedFoo = null;
38+
if (null) {
39+
(_a = null, exports.foo = exports.exportedFoo = _a.exportedFoo, exports.nfoo = exports.nonexportedFoo = nonexportedFoo = _a.nonexportedFoo);
40+
}
41+
else if (null) {
42+
(_b = null, exports.foo = exports.exportedFoo = _b.foo, exports.nfoo = exports.nonexportedFoo = nonexportedFoo = _b.bar);
43+
}
44+
else if (null) {
45+
(_c = null.foo, exports.foo = exports.exportedFoo = _c.bar, exports.nfoo = exports.nonexportedFoo = nonexportedFoo = _c.baz);
46+
}
47+
else if (null) {
48+
(_d = null, exports.foo = exports.exportedFoo = _d[0], exports.nfoo = exports.nonexportedFoo = nonexportedFoo = _d[1]);
49+
}
50+
else {
51+
(_e = null[0], exports.foo = exports.exportedFoo = _e[0], exports.nfoo = exports.nonexportedFoo = nonexportedFoo = _e[1]);
52+
}
53+
var _a, _b, _c, _d, _e;
Collapse file

‎tests/baselines/reference/destructuringAssignmentWithExportedName.symbols‎

Copy file name to clipboard
+54Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,54 @@
1+
=== tests/cases/compiler/destructuringAssignmentWithExportedName.ts ===
2+
export let exportedFoo: any;
3+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 0, 10))
4+
5+
let nonexportedFoo: any;
6+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 1, 3))
7+
8+
// sanity checks
9+
exportedFoo = null;
10+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 0, 10))
11+
12+
nonexportedFoo = null;
13+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 1, 3))
14+
15+
if (null as any) {
16+
({ exportedFoo, nonexportedFoo } = null as any);
17+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 8, 6))
18+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 8, 19))
19+
}
20+
else if (null as any) {
21+
({ foo: exportedFoo, bar: nonexportedFoo } = null as any);
22+
>foo : Symbol(foo, Decl(destructuringAssignmentWithExportedName.ts, 11, 3))
23+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 0, 10))
24+
>bar : Symbol(bar, Decl(destructuringAssignmentWithExportedName.ts, 11, 21))
25+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 1, 3))
26+
}
27+
else if (null as any) {
28+
({ foo: { bar: exportedFoo, baz: nonexportedFoo } } = null as any);
29+
>foo : Symbol(foo, Decl(destructuringAssignmentWithExportedName.ts, 14, 3))
30+
>bar : Symbol(bar, Decl(destructuringAssignmentWithExportedName.ts, 14, 10))
31+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 0, 10))
32+
>baz : Symbol(baz, Decl(destructuringAssignmentWithExportedName.ts, 14, 28))
33+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 1, 3))
34+
}
35+
else if (null as any) {
36+
([exportedFoo, nonexportedFoo] = null as any);
37+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 0, 10))
38+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 1, 3))
39+
}
40+
else {
41+
([[exportedFoo, nonexportedFoo]] = null as any);
42+
>exportedFoo : Symbol(exportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 0, 10))
43+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 1, 3))
44+
}
45+
46+
export { nonexportedFoo };
47+
>nonexportedFoo : Symbol(nonexportedFoo, Decl(destructuringAssignmentWithExportedName.ts, 23, 8))
48+
49+
export { exportedFoo as foo, nonexportedFoo as nfoo };
50+
>exportedFoo : Symbol(foo, Decl(destructuringAssignmentWithExportedName.ts, 24, 8))
51+
>foo : Symbol(foo, Decl(destructuringAssignmentWithExportedName.ts, 24, 8))
52+
>nonexportedFoo : Symbol(nfoo, Decl(destructuringAssignmentWithExportedName.ts, 24, 28))
53+
>nfoo : Symbol(nfoo, Decl(destructuringAssignmentWithExportedName.ts, 24, 28))
54+

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