import 'mocha';
import * as assert from 'assert';

import {preferSecond, flatten, groupConsecutiveElementsWhile, intersperse} from './../../src/helpers/array';

describe("Array Helpers Module", function(){

    describe("preferSecond()", function(){
        it('should return second element in an array, otherwise first or null', function() {
            assert.equal(preferSecond([1,3]), 3);
            assert.equal(preferSecond([5]), 5);
            assert.equal(preferSecond([]), null);
        });
    });

    describe("flatten()", function(){
        it('should return deeply flattened array', function() {
            assert.deepEqual(flatten([1,3, [4, [5, [6, 7]]]]), [
                1,3,4,5,6,7
            ]);
            assert.deepEqual(flatten([]), []);
        });
    });

    describe('groupConsecutiveElementsWhile()', function() {
        it('should move consecutive elements matching predicate into an arr', function() {
            var arr = [1, "ha", 3, "ha", "ha"]; 
            var grp = groupConsecutiveElementsWhile(arr, (v, v2) => typeof v === typeof v2);
            assert.deepEqual(grp, [1, "ha", 3, ["ha", "ha"]]);

            arr = [1, 2,3, 10,11,12]; 
            var grp = groupConsecutiveElementsWhile(arr, (v, v2) => v-1 === v2);
            assert.deepEqual(grp, [[1,2,3], [10,11,12]]);
        });
    });

    describe("intersperse()", function(){
        it('should put specified element between arr elements', function() {
            assert.deepEqual(intersperse([1,3, 4], 0), [
                1,0,3,0, 4
            ]);
            assert.deepEqual(intersperse([1],2), [1]);
        });
    });

});