--- /dev/null
+var ctx = require('./_ctx')
+ , call = require('./_iter-call')
+ , isArrayIter = require('./_is-array-iter')
+ , anObject = require('./_an-object')
+ , toLength = require('./_to-length')
+ , getIterFn = require('./core.get-iterator-method')
+ , BREAK = {}
+ , RETURN = {};
+var exports = module.exports = function(iterable, entries, fn, that, ITERATOR){
+ var iterFn = ITERATOR ? function(){ return iterable; } : getIterFn(iterable)
+ , f = ctx(fn, that, entries ? 2 : 1)
+ , index = 0
+ , length, step, iterator, result;
+ if(typeof iterFn != 'function')throw TypeError(iterable + ' is not iterable!');
+ // fast case for arrays with default iterator
+ if(isArrayIter(iterFn))for(length = toLength(iterable.length); length > index; index++){
+ result = entries ? f(anObject(step = iterable[index])[0], step[1]) : f(iterable[index]);
+ if(result === BREAK || result === RETURN)return result;
+ } else for(iterator = iterFn.call(iterable); !(step = iterator.next()).done; ){
+ result = call(iterator, f, step.value, entries);
+ if(result === BREAK || result === RETURN)return result;
+ }
+};
+exports.BREAK = BREAK;
+exports.RETURN = RETURN;
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