s-pipe/test/group_by.js

Functional streams, with a lisp-inspired chaining syntax

var _ = require('../_');


function floor(n) { return Math.floor(n); }


runMocha({
  'GroupByStream': {
    'group values synchronously': function() {
      deepEqual(_([4.2, 6.1, 6.4]).groupBy(floor).end(), [
        {key: 4, elements: [4.2]},
        {key: 6, elements: [6.1, 6.4]}
      ]);
    },

    'lazily evaluate the stream': function(done) {
      var result = [];
      var stream = _([4.2, 6.1, 6.4]).groupBy(floor).end(false);

      stream.on('data', function(n) { result.push(n); });
      stream.on('end', function() {
        deepEqual(result, [
          {key: 4, elements: [4.2]},
          {key: 6, elements: [6.1, 6.4]}
        ]);
        done();
      });
    }
  }
});