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36 lines
1.5 KiB
36 lines
1.5 KiB
'use strict'; |
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var ctx = require('./$.ctx') |
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, $export = require('./$.export') |
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, toObject = require('./$.to-object') |
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, call = require('./$.iter-call') |
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, isArrayIter = require('./$.is-array-iter') |
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, toLength = require('./$.to-length') |
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, getIterFn = require('./core.get-iterator-method'); |
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$export($export.S + $export.F * !require('./$.iter-detect')(function(iter){ Array.from(iter); }), 'Array', { |
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// 22.1.2.1 Array.from(arrayLike, mapfn = undefined, thisArg = undefined) |
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from: function from(arrayLike/*, mapfn = undefined, thisArg = undefined*/){ |
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var O = toObject(arrayLike) |
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, C = typeof this == 'function' ? this : Array |
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, $$ = arguments |
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, $$len = $$.length |
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, mapfn = $$len > 1 ? $$[1] : undefined |
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, mapping = mapfn !== undefined |
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, index = 0 |
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, iterFn = getIterFn(O) |
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, length, result, step, iterator; |
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if(mapping)mapfn = ctx(mapfn, $$len > 2 ? $$[2] : undefined, 2); |
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// if object isn't iterable or it's array with default iterator - use simple case |
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if(iterFn != undefined && !(C == Array && isArrayIter(iterFn))){ |
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for(iterator = iterFn.call(O), result = new C; !(step = iterator.next()).done; index++){ |
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result[index] = mapping ? call(iterator, mapfn, [step.value, index], true) : step.value; |
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} |
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} else { |
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length = toLength(O.length); |
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for(result = new C(length); length > index; index++){ |
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result[index] = mapping ? mapfn(O[index], index) : O[index]; |
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} |
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} |
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result.length = index; |
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return result; |
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} |
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});
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