1 | var assert = require('assert');
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2 | var slice = require('../lib/slice');
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3 |
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4 | var data = ['a', 'b', 'c', 'd', 'e', 'f'];
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5 |
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6 | suite('slice', function() {
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7 |
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8 | test('no params yields copy', function() {
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9 | assert.deepEqual(slice(data), data);
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10 | });
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11 |
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12 | test('no end param defaults to end', function() {
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13 | assert.deepEqual(slice(data, 2), data.slice(2));
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14 | });
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15 |
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16 | test('zero end param yields empty', function() {
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17 | assert.deepEqual(slice(data, 0, 0), []);
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18 | });
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19 |
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20 | test('first element with explicit params', function() {
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21 | assert.deepEqual(slice(data, 0, 1, 1), ['a']);
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22 | });
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23 |
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24 | test('last element with explicit params', function() {
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25 | assert.deepEqual(slice(data, -1, 6), ['f']);
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26 | });
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27 |
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28 | test('empty extents and negative step reverses', function() {
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29 | assert.deepEqual(slice(data, null, null, -1), ['f', 'e', 'd', 'c', 'b', 'a']);
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30 | });
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31 |
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32 | test('negative step partial slice', function() {
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33 | assert.deepEqual(slice(data, 4, 2, -1), ['e', 'd']);
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34 | });
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35 |
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36 | test('negative step partial slice no start defaults to end', function() {
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37 | assert.deepEqual(slice(data, null, 2, -1), ['f', 'e', 'd']);
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38 | });
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39 |
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40 | test('extents clamped end', function() {
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41 | assert.deepEqual(slice(data, null, 100), data);
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42 | });
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43 |
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44 | test('extents clamped beginning', function() {
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45 | assert.deepEqual(slice(data, -100, 100), data);
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46 | });
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47 |
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48 | test('backwards extents yields empty', function() {
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49 | assert.deepEqual(slice(data, 2, 1), []);
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50 | });
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51 |
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52 | test('zero step gets shot down', function() {
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53 | assert.throws(function() { slice(data, null, null, 0) });
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54 | });
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55 |
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56 | });
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57 |
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