Function distinct

A TransformStream that queues all items from a ReadableStream that are distinct by comparison from previous items.

If a selector function is provided, then it will project each value from the source observable into a new value that it will check for equality with previously projected values. If the selector function is not provided, it will use each value from the source observable directly with an equality check against previous values.

A long-running distinct use might result in memory leaks. To help alleviate this in some scenarios, an optional flushes parameter is also provided so that the internal Set can be "flushed", basically clearing it of values.

Example

A simple example with numbers

--1--1--2--2--2--1--2--3--4--3--2--1--

distinct()

--1-----2--------------3--4-----------
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An example using the selector function

--{a:4,n:'f'}--{a:7,n:'b'}--{a:5,n:'f'}--

distinct({ selector: ({ n }) => n })

--{a:4,n:'f'}--{a:7,n:'b'}---------------
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An example using the flushes parameter.

--1--1--2--2--2--1--2--3--4--3--2--1--

distinct({
flushes:
-------------F------------------------
})

--1-----2-----2--1-----3--4-----------
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