var concatMap = require('../');
var test = require('tape');

test('empty or not', function (t) {
  var xs = [1, 2, 3, 4, 5, 6];
  var ixes = [];
  var ys = concatMap(xs, function (x, ix) {
    ixes.push(ix);
    return x % 2 ? [x - 0.1, x, x + 0.1] : [];
  });
  t.same(ys, [0.9, 1, 1.1, 2.9, 3, 3.1, 4.9, 5, 5.1]);
  t.same(ixes, [0, 1, 2, 3, 4, 5]);
  t.end();
});

test('always something', function (t) {
  var xs = ['a', 'b', 'c', 'd'];
  var ys = concatMap(xs, function (x) {
    return x === 'b' ? ['B', 'B', 'B'] : [x];
  });
  t.same(ys, ['a', 'B', 'B', 'B', 'c', 'd']);
  t.end();
});

test('scalars', function (t) {
  var xs = ['a', 'b', 'c', 'd'];
  var ys = concatMap(xs, function (x) {
    return x === 'b' ? ['B', 'B', 'B'] : x;
  });
  t.same(ys, ['a', 'B', 'B', 'B', 'c', 'd']);
  t.end();
});

test('undefs', function (t) {
  var xs = ['a', 'b', 'c', 'd'];
  var ys = concatMap(xs, function () {});
  t.same(ys, [undefined, undefined, undefined, undefined]);
  t.end();
});