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x/ramda/test/findLastIndex.js

:ram: Practical functional Javascript
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var R = require('../source');var eq = require('./shared/eq');var listXf = require('./helpers/listXf');

describe('findLastIndex', function() { var obj1 = {x: 100}; var obj2 = {x: 200}; var a = [11, 10, 9, 'cow', obj1, 8, 7, 100, 200, 300, obj2, 4, 3, 2, 1, 0]; var even = function(x) { return x % 2 === 0; }; var gt100 = function(x) { return x > 100; }; var isStr = function(x) { return typeof x === 'string'; }; var xGt100 = function(o) { return o && o.x > 100; }; var intoArray = R.into([]);
it('returns the index of the last element that satisfies the predicate', function() { eq(R.findLastIndex(even, a), 15); eq(R.findLastIndex(gt100, a), 9); eq(R.findLastIndex(isStr, a), 3); eq(R.findLastIndex(xGt100, a), 10); });
it('returns -1 when no element satisfies the predicate', function() { eq(R.findLastIndex(even, ['zing']), -1); });
it('returns the index of the last element into an array that satisfies the predicate', function() { eq(intoArray(R.findLastIndex(even), a), [15]); eq(intoArray(R.findLastIndex(gt100), a), [9]); eq(intoArray(R.findLastIndex(isStr), a), [3]); eq(intoArray(R.findLastIndex(xGt100), a), [10]); });
it('returns -1 into an array when no element satisfies the predicate', function() { eq(intoArray(R.findLastIndex(even), ['zing']), [-1]); });
it('works when the first element matches', function() { eq(R.findLastIndex(even, [2, 3, 5]), 0); });
it('does not go into an infinite loop on an empty array', function() { eq(R.findLastIndex(even, []), -1); });
it('dispatches to transformer objects', function() { eq(R.findLastIndex(R.identity, listXf), { f: R.identity, idx: -1, lastIdx: -1, xf: listXf }); });});