accepts 1 input stream, an accumulator, a seed (optional)

  • The seed will be used as an initial accumulation acc
  • When the input stream emits a value v:
    • v and the latest acc are given to the accumulator
    • the returned value will be used as the next acc
  • When the input stream completes, the output stream emits the last acc and completes

returns a new stream of accumulated values



  • (coming soon)


Published on Monday, 12 Mar. 2018
Revised on Monday, 8 Oct. 2018

This is how a ❚ max operator would operate with an input stream:

  • When the input stream completes, the output stream:
    • emits the largest value emitted on the input stream
    • and immediately completes

Some reactive stream libraries (eg. RxJS) provide this ❚ max operator, while others don’t. How would you code max yourself?

Comparer function

In RxJS, ❚ min and ❚ max accept on optional comparer function as an argument.

For example:

See also

Pipeable operators - Build your own with RxJS!

Cédric Soulas Follow Hire me

Freelance Developer Advocate. Motion graphics with code. JavaScript and Elm.

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