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'use strict';
const common = require('../common');
const {
Readable,
} = require('stream');
const { deepStrictEqual, rejects, throws, strictEqual } = 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());
}
// Don't wait for next item in the original stream when already consumed the requested take amount
{
let reached = false;
let resolve;
const promise = new Promise((res) => resolve = res);
const stream = from((async function *() {
yield 1;
await promise;
reached = true;
yield 2;
})());
stream.take(1)
.toArray()
.then(common.mustCall(() => {
strictEqual(reached, false);
}))
.finally(() => resolve());
}
{
// 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/);
}
throws(() => Readable.from([1]).drop(1, 1), /ERR_INVALID_ARG_TYPE/);
throws(() => Readable.from([1]).drop(1, { signal: true }), /ERR_INVALID_ARG_TYPE/);
throws(() => Readable.from([1]).take(1, 1), /ERR_INVALID_ARG_TYPE/);
throws(() => Readable.from([1]).take(1, { signal: true }), /ERR_INVALID_ARG_TYPE/);
}
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