If initialValue is not specified, accumulator is initialized to the first value in the array, and callbackFn starts executing with the second value in the array as currentValue. If initialValue is specified, callbackFn starts executing with the first value in the array as currentValue. initialValue OptionalĪ value to which accumulator is initialized the first time the callback is called. On the first call, its value is 0 if initialValue is specified, otherwise 1. The index position of currentValue in the array. On the first call, its value is array if initialValue is specified otherwise its value is array. On the first call, its value is initialValue if the latter is specified otherwise its value is array. The value resulting from the previous call to callbackFn. The function is called with the following arguments: accumulator For the last invocation, the return value becomes the return value of reduce(). Its return value becomes the value of the accumulator parameter on the next invocation of callbackFn.
Object.prototype._defineSetter_() Deprecated.
