\n\n();\nconst writer = stream.writable.getWriter();\nconst reader = new StreamReader(stream.readable);\n\nstreamData({ writer });\n\nconst chunks = await reader.read();\n```\n\n
\n\n---\n\nBasic usage
\n\n```ts\nconst stream = new TransformStream\n\n
\n\n---\n\nReading chunk by chunk from a Response Body
\n\n```ts\nconst response = await fetch( ... )\nlet resourceSize = 0\n\nif ( response.body ) {\n const reader = new StreamReader( response.body )\n const decoder = new TextDecoder()\n reader.on( 'data', chunk => {\n const decoded = decoder.decode( chunk, { stream: true } )\n resourceSize += chunk.BYTES_PER_ELEMENT * chunk.length\n } )\n const chunks = await reader.read()\n}\n```\n\n\n\n();\nconst writer = stream.writable.getWriter();\nconst reader = new StreamReader(stream.readable, {\n transform(chunk) {\n return chunk.toString(\"base64url\");\n },\n});\n\nstreamData({ writer });\n\nreader.on(\"data\", (chunk) => {\n console.log(chunk); // chunk is now a base64url string\n});\nconst chunks = await reader.read(); // `string[]`\n```\n\n
\n\n---\n\nTransforming read chunks
\n\n```ts\nconst stream = new TransformStream\n\n();\nconst writer = stream.writable.getWriter();\nconst reader = new StreamReader(stream.readable, { inMemory });\n\nstreamData({ writer });\n\nreader.on(\"data\", (chunk) => {\n console.log(chunk);\n});\nconst chunks = await reader.read(); // void\n```\n\n
\n\n---\n\nOpting-out from in-memory chunk collection
\n\n```ts\nconst inMemory = false;\nconst stream = new TransformStream\n\n();\nconst writer = stream.writable.getWriter();\nconst reader = new StreamReader(stream.readable);\n\nstreamData({ writer });\n\nreader.read();\n\nabortButton.addEventListener(\"click\", () => {\n reader.abort(\"Reading no longer needed\");\n});\n```\n\n
\n\n---\n\n##### Error handling\n\nWhen an error occurs while reading stream data (such as unexpected stream abort), the `StreamReader` uses an internal `error` function which handles the thrown Error.\n\nBy default, if no listener is attached to the `error` event, the `StreamReader.read()` method will re-throw the caught error.\n\nIn that case, you need to await and wrap the `StreamReader.read()` method call in a `trycatch` block like so:\n\n```ts\ntry {\n const chunks = await reader.read();\n} catch (err) {\n const error = err as Error;\n console.error(\"An error occured\", error.message);\n}\n```\n\nwith `error` event listener:\n\n```ts\nreader.read();\nreader.on(\"error\", (error) => {\n console.error(\"An error occured\", error.message);\n});\n```\n\n---\n\n#### Types API Reference\n\n##### `ReadChunkAborting the reader before Stream is closed
\n\n```ts\nconst stream = new TransformStream\n  \n | \n \n
| \n