A ReadableStreamDefaultReader owns an exclusive read lock; releaseLock retires that handle. It does not close, cancel or drain the stream. Pending reads on the released reader reject with TypeError, while unread queued chunks stay in the stream and can be consumed by a new reader. Reader handle state and stream lifecycle must therefore be traced separately.
This specialist guide belongs to the Websites root. It also connects to The Gold Standard of Education | Learning That Transfers into Life and the How X Works hub. The worked cases are original teaching examples; their values and event logs are stated so each conclusion can be checked.
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Begin with stream S, reader R1 and one queued chunk. Record object identity, S.locked, R1.closed and every read promise. Release R1, acquire R2 and show which data and terminal state survive. The later chapters compare release with cancel, close and error, cover pending reads and show how pipeTo acquires ownership after a clean handoff.
ROUTE 1 · CHAPTERS 1–3
Build the first model
Name the input, state, conversion or predicate before following user-visible results.
ROUTE 2 · CHAPTERS 4–5
Trace the decisive branch
Work the accepted path and the nearest boundary case with original examples.
ROUTE 3 · CHAPTERS 6–8
Change one premise
Rebuild the mechanism when state, value, realm, timing or object kind changes.
ROUTE 4 · CHAPTERS 9–10
Handle limits and failures
Keep abrupt completion, availability and application limits visible.
ROUTE 5 · CHAPTERS 11–12
Verify and explain
Use a decisive fixture, changed-context check and concise final account.
Chapter contents
Build the first model · Chapters 1–3
1. Separate reader and stream identity
Trace the decisive branch · Chapters 4–5
Change one premise · Chapters 6–8
6. Acquire the next reader deliberately
Handle limits and failures · Chapters 9–10
Verify and explain · Chapters 11–12
The short answer is that a default reader is an exclusive consumer handle associated with one stream, while the stream and its queue exist independently of that handle. Chapter 1 focuses on separate reader and stream identity. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. create stream S with queued A, acquire R1 and record R1, S.locked and the untouched queue. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for separate reader and stream identity is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. release R1 and acquire R2; S and A are unchanged while the active reader identity changes. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: a reader variable is not the stream and cannot serve as its lifecycle record. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. assert object identities, lock transitions and the reader owning each read request. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of separate reader and stream identity should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that releaseLock clears the reader’s association and unlocks the stream without calling the underlying cancel algorithm or requesting stream closure. Chapter 2 focuses on release without closing or canceling. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. acquire R1, release it, acquire R2 and read A successfully with zero cancel callbacks. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for release without closing or canceling is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. call R1.cancel instead; the queue is discarded and the underlying cancel path runs. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: release describes capability ownership, not disposal of the readable resource. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. count close, error and cancel actions and prove release alone adds none. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of release without closing or canceling should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that if R1 has pending read requests when released, those promises reject with TypeError because that reader can no longer receive results. Chapter 3 focuses on reject pending reads on release. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. start P1 on an empty stream, release R1 and capture P1 rejection before acquiring R2. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for reject pending reads on release is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. enqueue A before release so P1 is already fulfilled; release no longer changes that settled result. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: the rejected promise reports handle retirement and is not a source error stored on S. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. assert TypeError for each pending R1 read and then prove S can still serve R2. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of reject pending reads on release should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that releasing a reader does not clear the stream queue, so chunks that R1 never requested remain available to a later reader. Chapter 4 focuses on preserve unread queued chunks. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. queue A and B, let R1 read A, release, acquire R2 and read B. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for preserve unread queued chunks is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. cancel R1 after reading A instead; B is discarded and R2 observes the closed stream. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: preserved queue order does not guarantee that application ownership transferred safely. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. record last R1 value, remaining queue order and first R2 value. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of preserve unread queued chunks should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
CHAPTER 5 OF 12 · Trace the decisive branch
5. Observe the released reader’s closed promise
The short answer is that after release from a readable stream that is not already errored, the old reader’s closed promise rejects with a release TypeError rather than following the stream’s later ordinary close. Chapter 5 focuses on observe the released reader’s closed promise. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. capture R1.closed, release, then close S under R2 and compare R1.closed with R2.closed. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for observe the released reader’s closed promise is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. error S before releasing R1; the reader preserves the stream error rather than replacing it with an ordinary release result. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: reader.closed belongs to a reader generation, not a permanent subscription to S. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. attach handlers before release and label every closed promise by reader identity. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of observe the released reader’s closed promise should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that a new reader can be acquired as soon as release unlocks the stream, but the application should define which records belong to the old and new ownership windows. Chapter 6 focuses on acquire the next reader deliberately. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. let R1 consume sequence 1, acknowledge it, release and let R2 consume sequence 2. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for acquire the next reader deliberately is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. release R1 while its processing of sequence 1 is still running; R2 can read 2 even though application work overlaps. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: the stream lock serializes reads, not all asynchronous processing performed after each read. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. record read ownership and application acknowledgement as separate events. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of acquire the next reader deliberately should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that release preserves the stream for another consumer, while reader.cancel expresses disinterest, closes the stream and invokes underlying cancellation. Chapter 7 focuses on distinguish release from cancel. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. run matched streams with queued A; release in one and cancel with R in the other. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for distinguish release from cancel is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. read A before either operation; the observed prefix matches but later capability and callback trails differ. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: both operations can make R1 inactive, so handle inactivity alone does not identify the cause. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. assert queue fate, cancel reason, S.locked and R2’s first read. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of distinguish release from cancel should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that natural source closure is a stream terminal event that can leave the reader locked until release, whereas release is only an ownership event. Chapter 8 focuses on distinguish release from natural closure. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. close S after queueing A, let R1 read A and done true, then release. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for distinguish release from natural closure is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. release before draining A; R2 receives A and the later done true result. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: unlocked and closed are independent properties and may occur in either order. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. record stream terminal event, done result and lock release separately. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of distinguish release from natural closure should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
CHAPTER 9 OF 12 · Handle limits and failures
9. Distinguish release from producer error
The short answer is that an errored stream stores its failure for readers, while releasing a healthy reader creates only handle-specific TypeErrors. Chapter 9 focuses on distinguish release from producer error. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. error S with E before release and show R1.closed plus later R2 observations retain E. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for distinguish release from producer error is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. release healthy R1 first, then error under R2; R1 shows release TypeError while R2 observes E. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: matching rejection types or messages across realms should not replace reason identity and event order. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. capture exact error objects and the state-changing actor for every rejection. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of distinguish release from producer error should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
CHAPTER 10 OF 12 · Handle limits and failures
10. Coordinate release with pipe ownership
The short answer is that pipeTo needs to acquire a reader and therefore cannot start while R1 still locks the source. Chapter 10 focuses on coordinate release with pipe ownership. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. release R1, start S.pipeTo(W), await the pipe and prove data transfer begins only after ownership changes. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for coordinate release with pipe ownership is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. call pipeTo before release; it rejects at the lock precondition and no destination write occurs. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: release makes the stream eligible for piping but does not prove application work on prior chunks is complete. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. await required acknowledgements, release, then assert pipe lock acquisition and ordered writes. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of coordinate release with pipe ownership should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that a safe handoff identifies the last record owned by R1, settles relevant application work, releases the lock and only then authorizes R2. Chapter 11 focuses on design a safe consumer handoff. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. R1 reads record 7, awaits processing receipt, releases and transfers a token that lets R2 acquire. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for design a safe consumer handoff is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. omit the processing receipt; R2 starts record 8 while record 7 can still fail downstream. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: reader release is a capability boundary, not a business transaction commit. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. store reader generation, last sequence, processing receipt and next acquisition time. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of design a safe consumer handoff should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
The short answer is that a complete receipt records stream identity, reader generations, queue order, pending reads, lock changes, closed-promise settlements, terminal cause and application acknowledgements. Chapter 12 focuses on build a reader-lifecycle receipt. Begin with keep stream identity, reader generation, lock state, queued chunks, pending read promises, reader.closed and stream terminal cause in separate columns. Writing those facts first prevents a familiar label or final summary value from replacing the mechanism or measurement basis that actually decides the result.
Worked example. run R1-to-R2 handoff with A and B, then close under R2 and publish the ordered trace. Treat every stated value as part of a controlled teaching fixture. Record the starting state before the operation, then record each conversion, selection, calculation, check or state transition in order. If a prerequisite fails, stop the trace there rather than inferring later effects from the usual path.
A useful first-principles question for build a reader-lifecycle receipt is: what must already be true before this step can run? Use the rule above to separate the input contract from the result. Follow object identity, state and returned value independently. Two branches can print similar data while differing in ownership, timing, brand or future capability.
Now change exactly one premise. replace close with error E and predict which reader promises and later reads change. Recalculate the trace from the changed fact rather than editing the old conclusion. Name the earliest event that differs, carry that difference through the remaining steps, and say which observations stay the same because their prerequisites did not change.
The main limit is this: the receipt proves one controlled handoff and does not authorize concurrent hidden consumers. Keep language semantics separate from processor strategy, host scheduling, browser support, trust policy and the meaning assigned by an application. A focused example can establish the stated mechanism without pretending to settle those broader questions.
Practical evidence check. verify all read and closed promises handled, no cancel callback on release and one terminal stream cause. Capture the reported values and failure conditions, but also preserve the calculation or event trail that led to them. A check that asserts only the last number or label can pass even when an earlier selection, conversion, grouping, state change or measurement basis was wrong.
A concise final explanation of build a reader-lifecycle receipt should state the starting state, the governing rule, the ordered outcome and one boundary. It should not depend on a screenshot, one software message or an unstated assumption. That form is short enough for revision and precise enough for a reproducible technical note.
Contents · Previous chapter · Return to the Websites subject guide
Frequently asked questions
Does releaseLock close the readable stream?
No. It only releases that reader’s exclusive lock.
What happens to pending reads?
Unsettled reads owned by the released reader reject with TypeError.
Are queued chunks lost?
No. Unread queued chunks remain available to a later reader.
What happens to the old reader.closed promise?
It rejects with the release error unless the reader had already adopted an existing stream error.
Can pipeTo start while a reader is active?
No. Release the reader after required work is settled, then start the pipe.
Is release the same as cancel?
No. Cancel closes the consumer-facing stream and invokes underlying cancellation.
Continue through the verified reading routes
Start with the wider system
The Gold Standard of Websites · The Gold Standard of Education | Learning That Transfers into Life · How X Works hub
Compare the closest mechanisms
The Gold Standard of Websites | Separating Response Body Locked State from Disturbed State · The Gold Standard of Websites | Tracing ReadableStream BYOB Minimum Fill and View Detachment · The Gold Standard of Websites | Separating Writer Lock Release from WritableStream Closure · The Gold Standard of Websites | Separating pipeTo Shutdown Controls Across preventAbort, preventCancel and preventClose · The Gold Standard of Websites | Separating pipeThrough Returned Readable from Its Internally Handled pipeTo Promise · The Gold Standard of Websites | Separating ReadableStream Close Requests from Queue Drain Completion · The Gold Standard of Websites | Separating ReadableStream Cancellation from Producer-Reported Errors
Choose the next lesson by reader job
Use the subject root to move from this focused mechanism to the next verified question. Follow a specialist link when its preconditions match your code; return to the wider hub when the next task belongs to a different system.
Authoritative sources and evidence checks
WHATWG Streams — pipeThrough method · WHATWG Streams — pipeTo method · WHATWG Streams — ReadableStreamPipeTo algorithm · WHATWG Streams — readable stream readers
The normative account follows the WHATWG Streams Living Standard. The worked fixtures report specified stream state, promise settlement and callback order; they do not infer network delivery, storage durability or application success from one fulfilled promise.