1 | 'use strict';
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2 | var $ = require('../internals/export');
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3 | var uncurryThis = require('../internals/function-uncurry-this');
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4 | var requireObjectCoercible = require('../internals/require-object-coercible');
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5 | var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
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6 | var toString = require('../internals/to-string');
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7 |
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8 | var stringSlice = uncurryThis(''.slice);
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9 | var max = Math.max;
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10 | var min = Math.min;
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11 |
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12 |
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13 | var FORCED = !''.substr || 'ab'.substr(-1) !== 'b';
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14 |
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15 |
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16 |
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17 | $({ target: 'String', proto: true, forced: FORCED }, {
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18 | substr: function substr(start, length) {
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19 | var that = toString(requireObjectCoercible(this));
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20 | var size = that.length;
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21 | var intStart = toIntegerOrInfinity(start);
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22 | var intLength, intEnd;
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23 | if (intStart === Infinity) intStart = 0;
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24 | if (intStart < 0) intStart = max(size + intStart, 0);
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25 | intLength = length === undefined ? size : toIntegerOrInfinity(length);
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26 | if (intLength <= 0 || intLength === Infinity) return '';
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27 | intEnd = min(intStart + intLength, size);
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28 | return intStart >= intEnd ? '' : stringSlice(that, intStart, intEnd);
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29 | }
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30 | });
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