1 | var toObject = require('../internals/to-object');
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2 | var toLength = require('../internals/to-length');
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3 | var getIteratorMethod = require('../internals/get-iterator-method');
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4 | var isArrayIteratorMethod = require('../internals/is-array-iterator-method');
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5 | var bind = require('../internals/bind-context');
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6 | var aTypedArrayConstructor = require('../internals/array-buffer-view-core').aTypedArrayConstructor;
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7 |
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8 | module.exports = function from(source /* , mapfn, thisArg */) {
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9 | var O = toObject(source);
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10 | var argumentsLength = arguments.length;
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11 | var mapfn = argumentsLength > 1 ? arguments[1] : undefined;
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12 | var mapping = mapfn !== undefined;
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13 | var iteratorMethod = getIteratorMethod(O);
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14 | var i, length, result, step, iterator, next;
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15 | if (iteratorMethod != undefined && !isArrayIteratorMethod(iteratorMethod)) {
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16 | iterator = iteratorMethod.call(O);
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17 | next = iterator.next;
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18 | O = [];
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19 | while (!(step = next.call(iterator)).done) {
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20 | O.push(step.value);
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21 | }
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22 | }
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23 | if (mapping && argumentsLength > 2) {
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24 | mapfn = bind(mapfn, arguments[2], 2);
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25 | }
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26 | length = toLength(O.length);
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27 | result = new (aTypedArrayConstructor(this))(length);
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28 | for (i = 0; length > i; i++) {
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29 | result[i] = mapping ? mapfn(O[i], i) : O[i];
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30 | }
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31 | return result;
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32 | };
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