Created
November 22, 2016 01:32
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Tail recursive inner functions to remove accumulator vars from the api
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| // Non tail recursive; will have a stack overflow. | |
| function sum(list) { | |
| if(list.length === 0) { | |
| return 0; | |
| } | |
| return list[0] + sum(list.slice(1)); | |
| } | |
| // Naive tail recursive (ugly api) | |
| function sum2(list, total = 0) { | |
| if(list.length === 0) { | |
| return total; | |
| } | |
| return sum2(list.slice(1), total + list[0]); | |
| } | |
| // Tail recursive using an inner function for a clean api | |
| function sum3(list) { | |
| let sumAccumulator = (list, total) => { | |
| return list.length === 0 ? | |
| total : | |
| sumAccumulator(list.slice(1), total + list[0]); | |
| }; | |
| return sumAccumulator(list, 0); | |
| } |
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