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25 lines
615 B
25 lines
615 B
/**
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* Calculate the # of periods to break-even on an initial investment,
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* given some array of cash flows for as many periods.
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*
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* Returns -1 if never break even.
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*/
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function payback_period(initial, flows = []) {
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let balance = -initial;
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let periods = 0;
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for ( const flow of flows ) {
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console.log({flow, balance, periods})
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if ( balance + flow > 0 ) {
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periods += (Math.abs(balance)) / flow;
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return periods;
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} else {
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balance += flow;
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periods += 1;
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}
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}
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return -1;
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}
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module.exports = exports = { payback_period } |