stream-union v1.0.2

stream-union

union of sorted streams

Installation

npm install stream-union

Example

var cmp = require('typewise-cmp')
function max(a, b) { return 0 <= cmp(a, b) ? a : b }

function getKey(item) { return item.key }
function maxValue(a, b) { return max(a.value, b.value) }

var union = require('stream-union')
    .using({ toKey: getKey, cmp: cmp, merge: maxValue })

…

API

union(aStream :: ReadableStream, bStream :: ReadableStream) -> ReadableStream

Union two sorted streams.

union.using({ toKey, cmp, merge }) -> function union(a, b) -> ReadableStream

Customise the behaviour of union. Returns a customised union function.

toKey :: function(item) -> key

the key function is applied to the items before comparison. it defaults to the identity function (a no-op).

cmp :: function(a, b) -> Number

a comparison function. return -1 for a < b, 1 for a > b and 0 for a = b. the default comparator considers values equal if they aren't less than or greater than each other.

merge :: function(a, b) -> item

the merge function is called with every equivalent pair of input items, and its return value is output on the union stream. if it returns undefined, nothing will be output. if it returns null, the union stream ends.