Should ReadableStreamDefaultReader be exposed? #586
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It's cunningly hidden here: https://streams.spec.whatwg.org/#globals If I was King Of The World I would explicitly mention it alongside each class definition as well. You can get it by doing something like const ReadableStreamDefaultReader = new ReadableStream().getReader().constructor;If there's a compelling use case for subclassing it then certainly it could be exposed. |
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Hah, yes, I missed that bit because I was looking for it alongside the class definition, but that's just where I'm used to seeing it on other specs. The above code is exactly what I used to get at the constructor. My usecase was adding |
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This is a conflict between ECMAScript style (expose only top-level classes) and web-style (expose everything). I've erred on the conservative side for now, since we can only go in one direction. The argument for exposing everything is, of course, this type of monkeypatching and polyfilling and instanceof testing and so on. I'm hesitant to do so before we hear more people wishing for it, but this is a good data point... |
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It turns out that switching to WebIDL (#963) makes the answer to this question "yes". WebIDL doesn't allow a type that is not exposed to be constructible. From https://heycam.github.io/webidl/#NoInterfaceObject:
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domenic
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Normative changes, all stemming from the Web IDL adaptation: * All classes are now exposed globally. Formerly, ReadableStreamDefaultReader, ReadableStreamBYOBReader, ReadableStreamDefaultController, ReadableByteStreamController, WritableStreamDefaultWriter, WritableStreamDefaultController, and TransformStreamDefaultController were not exposed. Closes #586. * All classes now have [Symbol.toStringTag] properties. (At least, pending whatwg/webidl#357 resolution.) Closes #952. * For the queuing strategy classes, their size and highWaterMark properties are now getters on the prototype, instead of data properties on the prototype and instance (respectively). Closes #1005. Note that the size function is not settable anymore, but highWaterMark has a setter. * Some functions have changed their length property value. * Some exceptions are thrown earlier, at argument-conversion time. Editorial changes: * All APIs are specified to using Web IDL now, instead of using a modified version of the ECMAScript specification conventions. We continue using abstract operations and completion records for now, and we have to drop down to the ECMAScript level in a couple places (notably for dealing with %ObjectPrototype% vs. null-prototype iteration result objects, and transferring array buffers). But overall this removes a lot of type-checking and conversion boilerplate from the specification. * Individual abstract operations, constructors, methods, and properties no longer have their own heading. They are instead lumped together in sections. Closes #885. * The constructors, methods, and properties are now documented in a per-class block, using the usual WHATWG "domintro" style. Closes #907. * Abstract operations are now consistently alphabetized within their section. Closes #684. * By using Bikeshed's <div algorithm> feature, we now get automatic identifier highlighting. Closes #687. * Switched to 100-character line limits, 1-space indents, and omitting end tags, per WHATWG conventions. * Removed usage of emu-algify in favor of using some more of Bikeshed's built-in features, plus manually annotating a few things. * Switched to concise Bikeshed linking syntax, e.g. [=term=] and [$AbstractOp$]. * Eliminated a number of utility abstract operations, especially around calling functions, by better using Web IDL. Other bug fixes: * Web IDL makes constructor behavior clear, so this closes #965.
domenic
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Normative changes, all stemming from the Web IDL adaptation: * All classes are now exposed globally. Formerly, ReadableStreamDefaultReader, ReadableStreamBYOBReader, ReadableStreamDefaultController, ReadableByteStreamController, WritableStreamDefaultWriter, WritableStreamDefaultController, and TransformStreamDefaultController were not exposed. Closes #586. * All classes now have [Symbol.toStringTag] properties. (At least, pending whatwg/webidl#357 resolution.) Closes #952. * All methods and accesors are now enumerable, per Web IDL defaults, instead of non-enumerable, per ECMAScript defaults. * For the queuing strategy classes, their size and highWaterMark properties are now getters on the prototype, instead of data properties on the prototype and instance (respectively). Closes #1005. Note that the size function is not settable anymore, but highWaterMark has a setter. * Some functions have changed their length property value. * Some exceptions are thrown earlier, at argument-conversion time. Editorial changes: * All APIs are specified to using Web IDL now, instead of using a modified version of the ECMAScript specification conventions. We continue using abstract operations and completion records for now, and we have to drop down to the ECMAScript level in a couple places (notably for dealing with %ObjectPrototype% vs. null-prototype iteration result objects, and transferring array buffers). But overall this removes a lot of type-checking and conversion boilerplate from the specification. * Individual abstract operations, constructors, methods, and properties no longer have their own heading. They are instead lumped together in sections. Closes #885. * The constructors, methods, and properties are now documented in a per-class block, using the usual WHATWG "domintro" style. Closes #907. * Abstract operations are now consistently alphabetized within their section. Closes #684. * By using Bikeshed's <div algorithm> feature, we now get automatic identifier highlighting. Closes #687. * Switched to 100-character line limits, 1-space indents, and omitting end tags, per WHATWG conventions. * Removed usage of emu-algify in favor of using some more of Bikeshed's built-in features, plus manually annotating a few things. * Switched to concise Bikeshed linking syntax, e.g. [=term=] and [$AbstractOp$]. * Eliminated a number of utility abstract operations, especially around calling functions, by better using Web IDL. Other bug fixes: * Web IDL makes constructor behavior clear, so this closes #965.
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domenic
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Normative changes, all stemming from the Web IDL adaptation: * All classes are now exposed globally. Formerly, ReadableStreamDefaultReader, ReadableStreamBYOBReader, ReadableStreamDefaultController, ReadableByteStreamController, WritableStreamDefaultWriter, WritableStreamDefaultController, and TransformStreamDefaultController were not exposed. Closes #586. * All classes now have [Symbol.toStringTag] properties. (At least, pending whatwg/webidl#357 resolution.) Closes #952. * All methods and accesors are now enumerable, per Web IDL defaults, instead of non-enumerable, per ECMAScript defaults. * For the queuing strategy classes, their size and highWaterMark properties are now getters on the prototype, instead of data properties on the prototype and instance (respectively). Closes #1005. Note that the size function is not settable anymore, but highWaterMark has a setter. * Some functions have changed their length property value. * Some exceptions are thrown earlier, at argument-conversion time. Editorial changes: * All APIs are specified to using Web IDL now, instead of using a modified version of the ECMAScript specification conventions. We continue using abstract operations and completion records for now, and we have to drop down to the ECMAScript level in a couple places (notably for dealing with %ObjectPrototype% vs. null-prototype iteration result objects, and transferring array buffers). But overall this removes a lot of type-checking and conversion boilerplate from the specification. * Individual abstract operations, constructors, methods, and properties no longer have their own heading. They are instead lumped together in sections. Closes #885. * The constructors, methods, and properties are now documented in a per-class block, using the usual WHATWG "domintro" style. Closes #907. * Abstract operations are now consistently alphabetized within their section. Closes #684. * By using Bikeshed's <div algorithm> feature, we now get automatic identifier highlighting. Closes #687. * Switched to 100-character line limits, 1-space indents, and omitting end tags, per WHATWG conventions. * Removed usage of emu-algify in favor of using some more of Bikeshed's built-in features, plus manually annotating a few things. * Switched to concise Bikeshed linking syntax, e.g. [=term=] and [$AbstractOp$]. * Eliminated a number of utility abstract operations, especially around calling functions, by better using Web IDL. Other bug fixes: * Web IDL makes constructor behavior clear, so this closes #965.
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Closes #963. Normative changes to widely-implemented features, roughly in order of most disruptive to least-disruptive: * For the queuing strategy classes, their size and highWaterMark properties are now getters on the prototype, instead of data properties on the prototype and instance (respectively). Closes #1005. In particular this means that attempts to set either of them post-creation will throw a TypeError. Chromium already ships these semantics. * Functions which take a dictionary no longer accept non-objects. * For the queuing strategy classes, their highWaterMark property will no longer return a non-number from their highWaterMark properties, if one was passed to the constructor. Instead, NaN will be returned. * All methods and accessors are now enumerable, per Web IDL defaults, instead of non-enumerable, per ECMAScript defaults. * All classes are now exposed globally. Formerly, ReadableStreamDefaultReader, ReadableStreamBYOBReader, ReadableStreamDefaultController, ReadableByteStreamController, WritableStreamDefaultWriter, WritableStreamDefaultController, and TransformStreamDefaultController were not exposed. Closes #586. * All classes now have [Symbol.toStringTag] properties. Closes #952. * Some functions have changed their length property value. * Some exceptions are thrown earlier, at argument-conversion time. * Property lookup in options arguments now happens earlier, at argument-conversion time, and in alphabetical order, per dictionary rules. Normative changes to unimplemented features: * ReadableStream's getIterator() method has been renamed to values() as part of adopting Web IDL's infrastructure for async iterators. * The byobRequest property on ReadableByteStreamController now returns null when there is no BYOB request, instead of returning undefined. * The view property on ReadableStreamBYOBRequest now returns null when the view cannot be written into, instead of returning undefined. * Various byte-stream-related APIs that used to specifically prohibit detached buffers now check for zero-length views or buffers, which is a more general category. * The async iterator's next() and return() methods now behave more like async generators, e.g. returning promises fulfilled with { value: undefined, done: true } after return()ing the iterator, instead of returning a rejected promise. Editorial changes: * All APIs are specified to using Web IDL now, instead of using a modified version of the ECMAScript specification conventions. We continue using abstract operations and completion records for now, and we have to drop down to the ECMAScript level in a couple places (notably for dealing with %ObjectPrototype% vs. null-prototype iteration result objects, and transferring array buffers). But overall this removes a lot of type-checking and conversion boilerplate from the specification. Closes #963. Closes #1017. See #1036 for further followup on the iteration result objects. * Individual abstract operations, constructors, methods, and properties no longer have their own heading. They are instead lumped together in sections. Closes #885. * The constructors, methods, and properties are now documented in a per-class block, using the usual WHATWG "domintro" style. Closes #907. * Abstract operations are now consistently alphabetized within their section. Closes #684. * By using Bikeshed's <div algorithm> feature, we now get automatic identifier highlighting. Closes #687. * Switched to 100-character line limits, 1-space indents, and omitting end tags, per WHATWG conventions. * Removed usage of emu-algify in favor of using some more of Bikeshed's built-in features, plus manually annotating a few things. * Switched to concise Bikeshed linking syntax, e.g. [=term=] and [$AbstractOp$]. * Eliminated a number of utility abstract operations, especially around calling functions, by better using Web IDL. Other bug fixes: * Web IDL makes constructor behavior clear, so this closes #965.
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Closes whatwg#963. Normative changes to widely-implemented features, roughly in order of most disruptive to least-disruptive: * For the queuing strategy classes, their size and highWaterMark properties are now getters on the prototype, instead of data properties on the prototype and instance (respectively). Closes whatwg#1005. In particular this means that attempts to set either of them post-creation will throw a TypeError. Chromium already ships these semantics. * Functions which take a dictionary no longer accept non-objects. * For the queuing strategy classes, their highWaterMark property will no longer return a non-number from their highWaterMark properties, if one was passed to the constructor. Instead, NaN will be returned. * All methods and accessors are now enumerable, per Web IDL defaults, instead of non-enumerable, per ECMAScript defaults. * All classes are now exposed globally. Formerly, ReadableStreamDefaultReader, ReadableStreamBYOBReader, ReadableStreamDefaultController, ReadableByteStreamController, WritableStreamDefaultWriter, WritableStreamDefaultController, and TransformStreamDefaultController were not exposed. Closes whatwg#586. * All classes now have [Symbol.toStringTag] properties. Closes whatwg#952. * Some functions have changed their length property value. * Some exceptions are thrown earlier, at argument-conversion time. * Property lookup in options arguments now happens earlier, at argument-conversion time, and in alphabetical order, per dictionary rules. Normative changes to unimplemented features: * ReadableStream's getIterator() method has been renamed to values() as part of adopting Web IDL's infrastructure for async iterators. * The byobRequest property on ReadableByteStreamController now returns null when there is no BYOB request, instead of returning undefined. * The view property on ReadableStreamBYOBRequest now returns null when the view cannot be written into, instead of returning undefined. * Various byte-stream-related APIs that used to specifically prohibit detached buffers now check for zero-length views or buffers, which is a more general category. * The async iterator's next() and return() methods now behave more like async generators, e.g. returning promises fulfilled with { value: undefined, done: true } after return()ing the iterator, instead of returning a rejected promise. Editorial changes: * All APIs are specified to using Web IDL now, instead of using a modified version of the ECMAScript specification conventions. We continue using abstract operations and completion records for now, and we have to drop down to the ECMAScript level in a couple places (notably for dealing with %ObjectPrototype% vs. null-prototype iteration result objects, and transferring array buffers). But overall this removes a lot of type-checking and conversion boilerplate from the specification. Closes whatwg#963. Closes whatwg#1017. See whatwg#1036 for further followup on the iteration result objects. * Individual abstract operations, constructors, methods, and properties no longer have their own heading. They are instead lumped together in sections. Closes whatwg#885. * The constructors, methods, and properties are now documented in a per-class block, using the usual WHATWG "domintro" style. Closes whatwg#907. * Abstract operations are now consistently alphabetized within their section. Closes whatwg#684. * By using Bikeshed's <div algorithm> feature, we now get automatic identifier highlighting. Closes whatwg#687. * Switched to 100-character line limits, 1-space indents, and omitting end tags, per WHATWG conventions. * Removed usage of emu-algify in favor of using some more of Bikeshed's built-in features, plus manually annotating a few things. * Switched to concise Bikeshed linking syntax, e.g. [=term=] and [$AbstractOp$]. * Eliminated a number of utility abstract operations, especially around calling functions, by better using Web IDL. Other bug fixes: * Web IDL makes constructor behavior clear, so this closes whatwg#965.
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The spec doesn't seem to cover which classes should be exposed where.
Right now
ReadableStreamDefaultReaderisn't exposed on the global. Should it be? Feels like it should be exposed somewhere for extensibility.The text was updated successfully, but these errors were encountered: