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fs: make offset, position & length args in fh.read() optional
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PR-URL: #51087
Fixes: #47183
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Vinícius Lourenço Claro Cardoso <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: James M Snell <[email protected]>
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pulkit-30 authored and richardlau committed Mar 25, 2024
1 parent dc3d70c commit a8fd01a
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Showing 3 changed files with 27 additions and 7 deletions.
13 changes: 8 additions & 5 deletions doc/api/fs.md
Original file line number Diff line number Diff line change
Expand Up @@ -385,11 +385,14 @@ added: v10.0.0
* `buffer` {Buffer|TypedArray|DataView} A buffer that will be filled with the
file data read.
* `offset` {integer} The location in the buffer at which to start filling.
* `length` {integer} The number of bytes to read.
* `position` {integer|null} The location where to begin reading data from the
file. If `null`, data will be read from the current file position, and
the position will be updated. If `position` is an integer, the current
file position will remain unchanged.
**Default:** `0`
* `length` {integer} The number of bytes to read. **Default:**
`buffer.byteLength - offset`
* `position` {integer|bigint|null} The location where to begin reading data
from the file. If `null` or `-1`, data will be read from the current file
position, and the position will be updated. If `position` is a non-negative
integer, the current file position will remain unchanged.
**Default:**: `null`
* Returns: {Promise} Fulfills upon success with an object with two properties:
* `bytesRead` {integer} The number of bytes read
* `buffer` {Buffer|TypedArray|DataView} A reference to the passed in `buffer`
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2 changes: 1 addition & 1 deletion lib/internal/fs/promises.js
Original file line number Diff line number Diff line change
Expand Up @@ -642,7 +642,7 @@ async function read(handle, bufferOrParams, offset, length, position) {
validateInteger(offset, 'offset', 0);
}

length |= 0;
length ??= buffer.byteLength - offset;

if (length === 0)
return { __proto__: null, bytesRead: length, buffer };
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19 changes: 18 additions & 1 deletion test/parallel/test-fs-promises-file-handle-read.js
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ const assert = require('assert');
const tmpDir = tmpdir.path;

async function read(fileHandle, buffer, offset, length, position, options) {
return options.useConf ?
return options?.useConf ?
fileHandle.read({ buffer, offset, length, position }) :
fileHandle.read(buffer, offset, length, position);
}
Expand Down Expand Up @@ -96,6 +96,21 @@ async function validateReadLength(len) {
assert.strictEqual(bytesRead, len);
}

async function validateReadWithNoOptions(byte) {
const buf = Buffer.alloc(byte);
const filePath = fixtures.path('x.txt');
const fileHandle = await open(filePath, 'r');
let response = await fileHandle.read(buf);
assert.strictEqual(response.bytesRead, byte);
response = await read(fileHandle, buf, 0, undefined, 0);
assert.strictEqual(response.bytesRead, byte);
response = await read(fileHandle, buf, 0, null, 0);
assert.strictEqual(response.bytesRead, byte);
response = await read(fileHandle, buf, 0, undefined, 0, { useConf: true });
assert.strictEqual(response.bytesRead, byte);
response = await read(fileHandle, buf, 0, null, 0, { useConf: true });
assert.strictEqual(response.bytesRead, byte);
}

(async function() {
tmpdir.refresh();
Expand All @@ -109,4 +124,6 @@ async function validateReadLength(len) {
await validateReadWithPositionZero();
await validateReadLength(0);
await validateReadLength(1);
await validateReadWithNoOptions(0);
await validateReadWithNoOptions(1);
})().then(common.mustCall());

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