12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879
var R = require('../source');var eq = require('./shared/eq');

describe('addIndex', function() {  describe('unary functions like `map`', function() {    var times2 = function(x) {return x * 2;};    var addIndexParam = function(x, idx) {return x + idx;};    var squareEnds = function(x, idx, list) {      return (idx === 0 || idx === list.length - 1) ? x * x : x;    };    var mapIndexed = R.addIndex(R.map);
    it('works just like a normal map', function() {      eq(mapIndexed(times2, [1, 2, 3, 4]), [2, 4, 6, 8]);    });
    it('passes the index as a second parameter to the callback', function() {      eq(mapIndexed(addIndexParam, [8, 6, 7, 5, 3, 0, 9]), [8, 7, 9, 8, 7, 5, 15]); // [8 + 0, 6 + 1...]    });
    it('passes the entire list as a third parameter to the callback', function() {      eq(mapIndexed(squareEnds, [8, 6, 7, 5, 3, 0, 9]), [64, 6, 7, 5, 3, 0, 81]);    });
    it('acts as a curried function', function() {      var makeSquareEnds = mapIndexed(squareEnds);      eq(makeSquareEnds([8, 6, 7, 5, 3, 0, 9]), [64, 6, 7, 5, 3, 0, 81]);    });
  });
  describe('binary functions like `reduce`', function() {    var reduceIndexed = R.addIndex(R.reduce);    var timesIndexed = function(tot, num, idx) {return tot + (num * idx);};    var objectify = function(acc, elem, idx) { acc[elem] = idx; return acc;};
    it('passes the index as a third parameter to the predicate', function() {      eq(reduceIndexed(timesIndexed, 0, [1, 2, 3, 4, 5]), 40);      eq(reduceIndexed(objectify, {}, ['a', 'b', 'c', 'd', 'e']), {a: 0, b: 1, c: 2, d: 3, e: 4});    });
    it('passes the entire list as a fourth parameter to the predicate', function() {      var list = [1, 2, 3];      reduceIndexed(function(acc, x, idx, ls) {        eq(ls, list);        return acc;      }, 0, list);    });
  });
  describe('works with functions like `all` that do not typically have index applied', function() {    var allIndexed = R.addIndex(R.all);    var superDiagonal = allIndexed(R.gt);    it('passes the index as a second parameter', function() {      eq(superDiagonal([8, 6, 5, 4, 9]), true); // 8 > 0, 6 > 1, 5 > 2, 4 > 3, 9 > 5      eq(superDiagonal([8, 6, 1, 3, 9]), false); //  1 !> 2, 3 !> 3    });
  });
  describe('works with arbitrary user-defined functions', function() {    var mapFilter = function(m, f, list) {      return R.filter(R.compose(f, m), list);    };    var mapFilterIndexed = R.addIndex(mapFilter);    it('passes the index as an additional parameter', function() {      eq(mapFilterIndexed(        R.multiply,        R.gt(R.__, 13),        [8, 6, 7, 5, 3, 0, 9]      ), [7, 5, 9]); // 2 * 7 > 13, 3 * 5 > 13, 6 * 9 > 13    });
  });
});