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from: Support 'mapfn'.

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David Braun 2017-10-22 02:59:29 -04:00
parent 6b577ea6cd
commit 8088d7e096
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GPG key ID: 5694EEC4D129BDCF
3 changed files with 16 additions and 4 deletions
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7
doc/API.md
View file

@ -12,7 +12,7 @@
- [Channel([bufferLength = 0]) -> Channel](#channelbufferlength--0---channel) - [Channel([bufferLength = 0]) -> Channel](#channelbufferlength--0---channel)
- [Channel.isChannel(value) -> Boolean](#channelischannelvalue---boolean) - [Channel.isChannel(value) -> Boolean](#channelischannelvalue---boolean)
- [Channel.of(...values) -> Channel](#channelofvalues---channel) - [Channel.of(...values) -> Channel](#channelofvalues---channel)
- [Channel.from(callback | iterable | stream.Readable) -> Channel](#channelfromcallback--iterable--streamreadable---channel) - [Channel.from(callback | iterable | stream.Readable[, mapfn [, thisArg]]) -> Channel](#channelfromcallback--iterable--streamreadable-mapfn--thisarg---channel)
- [Channel Object](#channel-object) - [Channel Object](#channel-object)
- [every(callbackfn[, thisArg]) -> async Boolean](#everycallbackfn-thisarg---async-boolean) - [every(callbackfn[, thisArg]) -> async Boolean](#everycallbackfn-thisarg---async-boolean)
- [filter(callbackfn[, thisArg]) -> Channel](#filtercallbackfn-thisarg---channel) - [filter(callbackfn[, thisArg]) -> Channel](#filtercallbackfn-thisarg---channel)
@ -164,7 +164,7 @@ Return `true` if `value` is a channel, `false` otherwise.
Push `values` into a new channel and then close it. Push `values` into a new channel and then close it.
### Channel.from(callback | iterable | stream.Readable) -> Channel ### Channel.from(callback | iterable | stream.Readable[, mapfn [, thisArg]]) -> Channel
Create a new `Channel` from a callback function, an iterable, or a [Node.js Create a new `Channel` from a callback function, an iterable, or a [Node.js
readable stream](https://nodejs.org/api/stream.html#stream_readable_streams). readable stream](https://nodejs.org/api/stream.html#stream_readable_streams).
@ -173,6 +173,9 @@ If given a callback function, call the function repeatedly to obtain values for
pushing into the channel. Close the channel when the function returns pushing into the channel. Close the channel when the function returns
`undefined`. `undefined`.
If the optional `mapfn` argument is provided, call it (using the also optional
`thisArg`) on each value before pushing it into the channel.
## Channel Object ## Channel Object
### every(callbackfn[, thisArg]) -> async Boolean ### every(callbackfn[, thisArg]) -> async Boolean

4
lib/index.js
View file

@ -306,7 +306,7 @@ const Channel = function(length = 0) {
); );
}; };
Channel.from = values => { Channel.from = (values, mapfn, thisArg) => {
const channel = Channel(); const channel = Channel();
(async () => { (async () => {
@ -349,7 +349,7 @@ Channel.from = values => {
} }
})(); })();
return channel; return mapfn ? channel.map(mapfn, thisArg) : channel;
}; };
Channel.of = (...values) => Channel.from(values); Channel.of = (...values) => Channel.from(values);

9
test/index.js
View file

@ -55,6 +55,15 @@ describe(`Channel`, function() {
assert.deepEqual(await Channel.from([0, 1, 2]).values(), [0, 1, 2]); assert.deepEqual(await Channel.from([0, 1, 2]).values(), [0, 1, 2]);
}); });
it(`mapfn`, async function() {
assert.deepEqual(
await Channel.from([`a`, `b`, `c`], value =>
value.toUpperCase()
).values(),
[`A`, `B`, `C`]
);
});
it(`Node.js's stream.readOnly`, async function() { it(`Node.js's stream.readOnly`, async function() {
const readOnly = stream.PassThrough({ objectMode: true }); const readOnly = stream.PassThrough({ objectMode: true });
readOnly.write(0); readOnly.write(0);