'use strict'; 
module.exports = function (arr, predicate, ctx){ 
if (typeof Array.prototype.findIndex === 'function') { 
return arr.findIndex(predicate, ctx); 
} 
if (typeof predicate !== 'function') { 
throw new TypeError('predicate must be a function')
} 
var list = Object(arr); 
var len = _AN_Read_length('length', list); 
if (len === 0) { 
return -1; 
} 
for (var i = 0; 
i < len; i++ ){ 
if (predicate.call(ctx, list[i], i, list)) { 
return i; 
} 
} 
return -1; 
} 
;