hinoki/test/readme-examples.js

sane, simple dependency injection and more

var test = require('tape');
var Promise = require('bluebird');

var hinoki = require('../lib/hinoki');

test('readme example', function(t) {
  var source = hinoki.source({
    sumFn: function() {
      return function(xs) {
        return xs.reduce(function(acc, x) { return acc + x; }, 0);
      }
    },
    numbersSquared: function(numbers) {
      return numbers.map(function(x) { return x * x; });
    },
    numbersSorted: function(numbers) {
      return numbers.slice().sort(function(a, b) { return a - b; });
    },
    count: function(numbers) {
      return numbers.length;
    },
    median: function(numbersSorted, count) {
      return numbersSorted[Math.round(count / 2)];
    },
    mean: function(numbers, count, sumFn) {
      return sumFn(numbers) / count;
    },
    meanOfSquares: function(numbersSquared, count, sumFn) {
      return sumFn(numbersSquared) / count;
    },
    variance: function(mean, meanOfSquares) {
      return meanOfSquares - mean * mean;
    }
  });

  var lifetime = {
    // TODO shuffle this around
    numbers: [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
  };

  hinoki(source, lifetime, 'mean')
    .then(function(mean) {
      t.equal(mean, 8.8);
      return hinoki(source, lifetime, ['mean', 'variance', 'numbersSorted']);
    })
    .spread(function(mean, variance, numbersSorted) {
      console.log('mean', mean); // ->
      console.log('variance', variance); // ->
      console.log('numbersSorted', numbersSorted); // ->
      return hinoki(source, lifetime, function(variance, median) {
        console.log('variance', variance); // ->
        console.log('median', median); // ->
      });
    })
    .then(function() {
      t.end();
    });
});