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							- module.exports = function (xs, fn) {
 
-     var res = [];
 
-     for (var i = 0; i < xs.length; i++) {
 
-         var x = fn(xs[i], i);
 
-         if (isArray(x)) res.push.apply(res, x);
 
-         else res.push(x);
 
-     }
 
-     return res;
 
- };
 
- var isArray = Array.isArray || function (xs) {
 
-     return Object.prototype.toString.call(xs) === '[object Array]';
 
- };
 
 
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