take
accepts
1 input stream,
an amount
-
❯When the input stream emits its n-th value:
- if n <
amount, the value is emitted - if n ==
amount, the value is emitted and the stream immediately completes
- if n <
returns
a new stream of at most amount values
takeLast
accepts
1 input stream,
an amount
-
❯When the input stream completes, the output stream:
- emits each of the last
amountvalues emitted by the input stream (they are emitted as separate event values) - and immediately completes
- emits each of the last
- ❯If the input stream never completes, the output stream never emits
returns
a new stream of at most amount values
Revised on Monday, 8 Oct. 2018
Learn more about stream completion.
Use a ▬ number on these cards, such as 3, to set a maximum amount of events to emit. ❚ take and ❚ takeLast share identical behavior:
- they both return a new stream of at most amount values.
- if the input stream source emits fewer than amount values then all of its values are emitted on the output stream.
The stream returned by ❚ take emits the values at the same time as their counterpart on the input stream. This is not the case for ❚ takeLast. Remember: a stream is a sequence of events over time. And we can’t see the future! takeLast must wait for the ◉ complete notification. Only then, we know what are the last values.
See also
Freelance Developer Advocate. Motion graphics with code. JavaScript and Elm. cedricsoulas.com
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