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iter-ops-extras

:star: Collection of custom operators for iter-ops - ones based on existing operators.

:bulb: It is here to show implementation examples, plus share ideas of useful operations.

:clipboard: These are just quick copy-n-paste snippets, they are not distributed anywhere.

:mega: Feel free submitting PR-s with your own custom operators, to share with others.

• appendIf - conditionally injects value(s) after the current value.
• average - emits an average value, with optional key selector.
• distinctUntilChanged - filters out repeated values.
• distinctValues - selects unique key-values, then remaps into just values.
• flat/flatMap - replacement for default ones, to replicate Array's methods.
• group - groups objects by a property value.
• interval - the same as delay, but without delaying the first value.
• join - joins strings, with optional separator.
• mapWait - remaps and sequentially awaits promises.
• max - emits maximum value, with optional key selector.
• min - emits minimum value, with optional key selector.
• numberStats - emits basic number statistics: {min, max, avg, sum, count}.
• pluck - maps each value to its specified nested property.
• prependIf - conditionally injects value(s) before the current value.
• removeNotType - removes values that are not of specified primitive type(s).
• removeType - removes values of specified primitive type(s).
• removeNil - removes all null and undefined values.
• repeatAll - repeats the entire iterable N times.
• replaceIf - conditionally injects value(s) in place of the current value.
• replaceNil - replaces every null and undefined with an alternative value.
• slice - implements Array->slice logic (for positive start/end only).
• sum - sums up values, with optional key selector.
• tapLog - logs values into the console, with optional tag + selector.
• tapOnce - taps into the very first value only.
• toBuffer - emits a Buffer from the iterable.
• toReadable - emits a Readable stream from the iterable.

To use these, create a folder in your project, and copy over either select operators or the entire ./src folder, which also has file ./src/index.ts that includes everything.

Some of these operators may eventually land in the main iter-ops library. Use Discussions, if you want to propose and vote on such additions.

See also Custom Operators - explains API for custom operators.

:bulb: TIP: Operators consume and concurrencyFork are useful helpers for custom operators.