filter a stream of objects by their key property

filter_stream_example.js

var Stream = require('stream.js') // https://github.com/dionyziz/stream.js

var myStream = Stream.make({
  key:'please'
}, {
  key: 'filter'
}, {
  key: 'this'
}, {
  key: 'data'
})

var FilterByKey = S => contains_str => S.filter(item => ~item.key.indexOf(contains_str))

var myFilter = FilterByKey(myStream)

myFilter('a').print() 
/* 
{ key: 'please' }
{ key: 'data' }
*/

myFilter('i').print()
/*
{ key: 'filter' }
{ key: 'this' }
*/