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1. Performs left to right composition of one or more functions that return a promise

   JavaScript 11 2

2. Runs an array of promises in series, each passing their results to the next promise in the array.

   JavaScript 12 7

3. Returns a promise containing the result of the promisified mappingFn on its elements.

   JavaScript 2

4. Returns a promise containing the reduced result from the provided function

   JavaScript 1