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rkirovrkirov
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do not emit double assigment of class expressions.
Closure compiler ES6 support rejects expressions of the form `let A = B = class {}` With a small rewriting of the emitted code the case of decorated and staticly referenced classes, TypeScript ES6 emit satisfies this requirement. Before: let C_1; let C = C_1 = class C {}; After: let C_1 = class C {}; let C_1 = C;
1 parent 7173fa8 commit 699dc4f

4 files changed

Lines changed: 34 additions & 24 deletions

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‎src/compiler/emitter.ts‎

Lines changed: 28 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -5359,17 +5359,17 @@ const _super = (function (geti, seti) {
53595359
//
53605360
// TypeScript | Javascript
53615361
// --------------------------------|------------------------------------
5362-
// @dec | let C_1;
5363-
// class C { | let C = C_1 = class C {
5364-
// static x() { return C.y; } | static x() { return C_1.y; }
5365-
// static y = 1; | }
5362+
// @dec | let C_1 = class C {
5363+
// class C { | static x() { return C_1.y; }
5364+
// static x() { return C.y; } | }
5365+
// static y = 1; | let C = C_1;
53665366
// } | C.y = 1;
53675367
// | C = C_1 = __decorate([dec], C);
53685368
// --------------------------------|------------------------------------
5369-
// @dec | let C_1;
5370-
// export class C { | export let C = C_1 = class C {
5371-
// static x() { return C.y; } | static x() { return C_1.y; }
5372-
// static y = 1; | }
5369+
// @dec | let C_1 = class C {
5370+
// export class C { | static x() { return C_1.y; }
5371+
// static x() { return C.y; } | }
5372+
// static y = 1; | export let C = C_1;
53735373
// } | C.y = 1;
53745374
// | C = C_1 = __decorate([dec], C);
53755375
// ---------------------------------------------------------------------
@@ -5398,10 +5398,10 @@ const _super = (function (geti, seti) {
53985398
//
53995399
// TypeScript | Javascript
54005400
// --------------------------------|------------------------------------
5401-
// @dec | let C_1;
5402-
// export default class C { | let C = C_1 = class C {
5403-
// static x() { return C.y; } | static x() { return C_1.y; }
5404-
// static y = 1; | }
5401+
// @dec | let C_1 = class C {
5402+
// export default class C { | static x() { return C_1.y; }
5403+
// static x() { return C.y; } | };
5404+
// static y = 1; | let C = C_1;
54055405
// } | C.y = 1;
54065406
// | C = C_1 = __decorate([dec], C);
54075407
// | export default C;
@@ -5410,25 +5410,25 @@ const _super = (function (geti, seti) {
54105410
//
54115411

54125412
// NOTE: we reuse the same rewriting logic for cases when targeting ES6 and module kind is System.
5413-
// Because of hoisting top level class declaration need to be emitted as class expressions.
5413+
// Because of hoisting top level class declaration need to be emitted as class expressions.
54145414
// Double bind case is only required if node is decorated.
54155415
if (isDecorated && resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithBodyScopedClassBinding) {
54165416
decoratedClassAlias = unescapeIdentifier(makeUniqueName(node.name ? node.name.text : "default"));
54175417
decoratedClassAliases[getNodeId(node)] = decoratedClassAlias;
5418-
write(`let ${decoratedClassAlias};`);
5419-
writeLine();
54205418
}
54215419

5422-
if (isES6ExportedDeclaration(node) && !(node.flags & NodeFlags.Default)) {
5420+
if (isES6ExportedDeclaration(node) && !(node.flags & NodeFlags.Default) && decoratedClassAlias === undefined) {
54235421
write("export ");
54245422
}
54255423

54265424
if (!isHoistedDeclarationInSystemModule) {
54275425
write("let ");
54285426
}
5429-
emitDeclarationName(node);
54305427
if (decoratedClassAlias !== undefined) {
5431-
write(` = ${decoratedClassAlias}`);
5428+
write(`${decoratedClassAlias}`);
5429+
}
5430+
else {
5431+
emitDeclarationName(node);
54325432
}
54335433

54345434
write(" = ");
@@ -5490,6 +5490,16 @@ const _super = (function (geti, seti) {
54905490
emitToken(SyntaxKind.CloseBraceToken, node.members.end);
54915491

54925492
if (rewriteAsClassExpression) {
5493+
if (decoratedClassAlias !== undefined) {
5494+
write(";");
5495+
writeLine();
5496+
if (isES6ExportedDeclaration(node) && !(node.flags & NodeFlags.Default)) {
5497+
write("export ");
5498+
}
5499+
write("let ");
5500+
emitDeclarationName(node);
5501+
write(` = ${decoratedClassAlias}`);
5502+
}
54935503
decoratedClassAliases[getNodeId(node)] = undefined;
54945504
write(";");
54955505
}

‎tests/baselines/reference/decoratorOnClass5.es6.js‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -16,10 +16,10 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
1616
else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
1717
return c > 3 && r && Object.defineProperty(target, key, r), r;
1818
};
19-
let C_1;
20-
let C = C_1 = class C {
19+
let C_1 = class C {
2120
static x() { return C_1.y; }
2221
};
22+
let C = C_1;
2323
C.y = 1;
2424
C = C_1 = __decorate([
2525
dec

‎tests/baselines/reference/decoratorOnClass6.es6.js‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -16,10 +16,10 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
1616
else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
1717
return c > 3 && r && Object.defineProperty(target, key, r), r;
1818
};
19-
let C_1;
20-
export let C = C_1 = class C {
19+
let C_1 = class C {
2120
static x() { return C_1.y; }
2221
};
22+
export let C = C_1;
2323
C.y = 1;
2424
C = C_1 = __decorate([
2525
dec

‎tests/baselines/reference/decoratorOnClass7.es6.js‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -16,10 +16,10 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
1616
else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
1717
return c > 3 && r && Object.defineProperty(target, key, r), r;
1818
};
19-
let C_1;
20-
let C = C_1 = class C {
19+
let C_1 = class C {
2120
static x() { return C_1.y; }
2221
};
22+
let C = C_1;
2323
C.y = 1;
2424
C = C_1 = __decorate([
2525
dec

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