co-stream-map

co-stream-map

Map a co stream over each chunk of another co stream.

Example

Given a stream twice that emits strings and a stream chars the emits a string's chars, map chars over twice:

var map = require('co-stream-map');

// a stream that emits `str` twice

function twice(str){
  var i = 0;
  return function*(end){
    if (end) return;
    if (++i <3) return str;
  }
}

// a stream that emits `str` split up into chars

function chars(str){
  return function*(end){
    if (end) return;
    var first = str[0];
    str = str.slice(1);
    return first;
  }
}

var source = twice('bar');
var read = map(source, chars);

assert.equal('b', yield read());
assert.equal('a', yield read());
assert.equal('r', yield read());
assert.equal('b', yield read());
assert.equal('a', yield read());
assert.equal('r', yield read());
assert(!(yield read()));

API

map(stream, fn)

For every chunk stream emits, call fn with that chunk and read from the returned stream.

fn can be a Function or a GeneratorFunction.

Returns a readable stream.

Installation

$ npm install co-stream-map

License

MIT