Support using and await using declarations
#54505
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@@ -136,6 +136,9 @@ export interface EmitHelperFactory { | |
| createClassPrivateFieldGetHelper(receiver: Expression, state: Identifier, kind: PrivateIdentifierKind, f: Identifier | undefined): Expression; | ||
| createClassPrivateFieldSetHelper(receiver: Expression, state: Identifier, value: Expression, kind: PrivateIdentifierKind, f: Identifier | undefined): Expression; | ||
| createClassPrivateFieldInHelper(state: Identifier, receiver: Expression): Expression; | ||
| // 'using' helpers | ||
| createAddDisposableResourceHelper(envBinding: Expression, value: Expression, async: boolean): Expression; | ||
| createDisposeResourcesHelper(envBinding: Expression): Expression; | ||
| } | ||
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| /** @internal */ | ||
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@@ -183,7 +186,10 @@ export function createEmitHelperFactory(context: TransformationContext): EmitHel | |
| // Class Fields Helpers | ||
| createClassPrivateFieldGetHelper, | ||
| createClassPrivateFieldSetHelper, | ||
| createClassPrivateFieldInHelper, | ||
| // 'using' helpers | ||
| createAddDisposableResourceHelper, | ||
| createDisposeResourcesHelper, | ||
| }; | ||
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| /** | ||
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@@ -666,6 +672,20 @@ export function createEmitHelperFactory(context: TransformationContext): EmitHel | |
| context.requestEmitHelper(classPrivateFieldInHelper); | ||
| return factory.createCallExpression(getUnscopedHelperName("__classPrivateFieldIn"), /*typeArguments*/ undefined, [state, receiver]); | ||
| } | ||
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| function createAddDisposableResourceHelper(envBinding: Expression, value: Expression, async: boolean): Expression { | ||
| context.requestEmitHelper(addDisposableResourceHelper); | ||
| return factory.createCallExpression( | ||
| getUnscopedHelperName("__addDisposableResource"), | ||
| /*typeArguments*/ undefined, | ||
| [envBinding, value, async ? factory.createTrue() : factory.createFalse()] | ||
| ); | ||
| } | ||
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| function createDisposeResourcesHelper(envBinding: Expression) { | ||
| context.requestEmitHelper(disposeResourcesHelper); | ||
| return factory.createCallExpression(getUnscopedHelperName("__disposeResources"), /*typeArguments*/ undefined, [envBinding]); | ||
| } | ||
| } | ||
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| /** @internal */ | ||
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@@ -1367,6 +1387,71 @@ export const classPrivateFieldInHelper: UnscopedEmitHelper = { | |
| };` | ||
| }; | ||
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| /** | ||
| * @internal | ||
| */ | ||
| export const addDisposableResourceHelper: UnscopedEmitHelper = { | ||
| name: "typescript:addDisposableResource", | ||
| importName: "__addDisposableResource", | ||
| scoped: false, | ||
| text: ` | ||
| var __addDisposableResource = (this && this.__addDisposableResource) || function (env, value, async) { | ||
| if (value !== null && value !== void 0) { | ||
| if (typeof value !== "object") throw new TypeError("Object expected."); | ||
| var dispose; | ||
| if (async) { | ||
| if (!Symbol.asyncDispose) throw new TypeError("Symbol.asyncDispose is not defined."); | ||
| dispose = value[Symbol.asyncDispose]; | ||
| } | ||
| if (dispose === void 0) { | ||
| if (!Symbol.dispose) throw new TypeError("Symbol.dispose is not defined."); | ||
| dispose = value[Symbol.dispose]; | ||
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There was a problem hiding this comment. In Babel we use class MyResource {
[Symbol.dispose || Symbol.for("Symbol.dispose")]() {}
}and they will be usable both natively and in older environments. It might be great to align on this. There was a problem hiding this comment. TypeScript helpers generally don't polyfill/shim Symbols in this way. We usually depend on the developer to introduce any necessary global shim instead. I'm curious if @DanielRosenwasser has any thoughts on this approach, however. There was a problem hiding this comment. We discussed this in design meeting and don't believe TypeScript should support Babel supporting for While I think it is commendable to support users' efforts to avoid global scope modifications, I don't think this is an approach TypeScript can take here. I'd even go so far as to recommend that Babel not provide such support, but given that Babel's support for I'll also note that, since the native |
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| } | ||
| if (typeof dispose !== "function") throw new TypeError("Object not disposable."); | ||
| env.stack.push({ value: value, dispose: dispose, async: async }); | ||
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There was a problem hiding this comment. Unrelated: at what point will it be OK for us to use es6 features like object shorthands in our esnext downlevel helpers? There was a problem hiding this comment. If our helpers were an AST instead of a string, then we could arguably downlevel them on demand. Unfortunately, that wouldn't work for |
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| } | ||
| else if (async) { | ||
| env.stack.push({ async: true }); | ||
| } | ||
| return value; | ||
| };` | ||
| }; | ||
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| /** | ||
| * @internal | ||
| */ | ||
| export const disposeResourcesHelper: UnscopedEmitHelper = { | ||
| name: "typescript:disposeResources", | ||
| importName: "__disposeResources", | ||
| scoped: false, | ||
| text: ` | ||
| var __disposeResources = (this && this.__disposeResources) || (function (SuppressedError) { | ||
| return function (env) { | ||
| function fail(e) { | ||
| env.error = env.hasError ? new SuppressedError(e, env.error, "An error was suppressed during disposal.") : e; | ||
| env.hasError = true; | ||
| } | ||
| function next() { | ||
| while (env.stack.length) { | ||
| var rec = env.stack.pop(); | ||
| try { | ||
| var result = rec.dispose && rec.dispose.call(rec.value); | ||
| if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); }); | ||
| } | ||
| catch (e) { | ||
| fail(e); | ||
| } | ||
| } | ||
| if (env.hasError) throw env.error; | ||
| } | ||
| return next(); | ||
| }; | ||
| })(typeof SuppressedError === "function" ? SuppressedError : function (error, suppressed, message) { | ||
| var e = new Error(message); | ||
| return e.name = "SuppressedError", e.error = error, e.suppressed = suppressed, e; | ||
| });` | ||
| }; | ||
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| let allUnscopedEmitHelpers: ReadonlyMap<string, UnscopedEmitHelper> | undefined; | ||
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| /** @internal */ | ||
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@@ -1399,7 +1484,9 @@ export function getAllUnscopedEmitHelpers() { | |
| classPrivateFieldSetHelper, | ||
| classPrivateFieldInHelper, | ||
| createBindingHelper, | ||
| setModuleDefaultHelper, | ||
| addDisposableResourceHelper, | ||
| disposeResourcesHelper, | ||
| ], helper => helper.name)); | ||
| } | ||
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