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author | Benjamin Gruenbaum <benjamingr@gmail.com> | 2022-01-21 19:42:21 +0300 |
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committer | Benjamin Gruenbaum <benjamingr@gmail.com> | 2022-01-23 19:43:16 +0300 |
commit | a8afe26fca2d3a7c374f86834525084e10ddc1a1 (patch) | |
tree | 7309be337554092b4978ed0130c1d7695b6c8f53 /test | |
parent | 3d27a04b5647d3a357f940dff24603b19da08767 (diff) |
stream: add drop and take
This adds the `drop` and `take` methods to readable streams allowing
users easily drop and take items from the stream.
This continues the iterator-helper proposal alignment task.
Co-Authored-By: Robert Nagy <ronagy@icloud.com>
PR-URL: https://github.com/nodejs/node/pull/41630
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Diffstat (limited to 'test')
-rw-r--r-- | test/parallel/test-stream-drop-take.js | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/test/parallel/test-stream-drop-take.js b/test/parallel/test-stream-drop-take.js new file mode 100644 index 00000000000..ddeb6054a78 --- /dev/null +++ b/test/parallel/test-stream-drop-take.js @@ -0,0 +1,96 @@ +'use strict'; + +const common = require('../common'); +const { + Readable, +} = require('stream'); +const { deepStrictEqual, rejects, throws } = require('assert'); + +const { from } = Readable; + +const fromAsync = (...args) => from(...args).map(async (x) => x); + +const naturals = () => from(async function*() { + let i = 1; + while (true) { + yield i++; + } +}()); + +{ + // Synchronous streams + (async () => { + deepStrictEqual(await from([1, 2, 3]).drop(2).toArray(), [3]); + deepStrictEqual(await from([1, 2, 3]).take(1).toArray(), [1]); + deepStrictEqual(await from([]).drop(2).toArray(), []); + deepStrictEqual(await from([]).take(1).toArray(), []); + deepStrictEqual(await from([1, 2, 3]).drop(1).take(1).toArray(), [2]); + deepStrictEqual(await from([1, 2]).drop(0).toArray(), [1, 2]); + deepStrictEqual(await from([1, 2]).take(0).toArray(), []); + })().then(common.mustCall()); + // Asynchronous streams + (async () => { + deepStrictEqual(await fromAsync([1, 2, 3]).drop(2).toArray(), [3]); + deepStrictEqual(await fromAsync([1, 2, 3]).take(1).toArray(), [1]); + deepStrictEqual(await fromAsync([]).drop(2).toArray(), []); + deepStrictEqual(await fromAsync([]).take(1).toArray(), []); + deepStrictEqual(await fromAsync([1, 2, 3]).drop(1).take(1).toArray(), [2]); + deepStrictEqual(await fromAsync([1, 2]).drop(0).toArray(), [1, 2]); + deepStrictEqual(await fromAsync([1, 2]).take(0).toArray(), []); + })().then(common.mustCall()); + // Infinite streams + // Asynchronous streams + (async () => { + deepStrictEqual(await naturals().take(1).toArray(), [1]); + deepStrictEqual(await naturals().drop(1).take(1).toArray(), [2]); + const next10 = [11, 12, 13, 14, 15, 16, 17, 18, 19, 20]; + deepStrictEqual(await naturals().drop(10).take(10).toArray(), next10); + deepStrictEqual(await naturals().take(5).take(1).toArray(), [1]); + })().then(common.mustCall()); +} + +{ + // Coercion + (async () => { + // The spec made me do this ^^ + deepStrictEqual(await naturals().take('cat').toArray(), []); + deepStrictEqual(await naturals().take('2').toArray(), [1, 2]); + deepStrictEqual(await naturals().take(true).toArray(), [1]); + })().then(common.mustCall()); +} + +{ + // Support for AbortSignal + const ac = new AbortController(); + rejects( + Readable.from([1, 2, 3]).take(1, { signal: ac.signal }).toArray(), { + name: 'AbortError', + }).then(common.mustCall()); + rejects( + Readable.from([1, 2, 3]).drop(1, { signal: ac.signal }).toArray(), { + name: 'AbortError', + }).then(common.mustCall()); + ac.abort(); +} + +{ + // Support for AbortSignal, already aborted + const signal = AbortSignal.abort(); + rejects( + Readable.from([1, 2, 3]).take(1, { signal }).toArray(), { + name: 'AbortError', + }).then(common.mustCall()); +} + +{ + // Error cases + const invalidArgs = [ + -1, + -Infinity, + -40, + ]; + + for (const example of invalidArgs) { + throws(() => from([]).take(example).toArray(), /ERR_OUT_OF_RANGE/); + } +} |