X-Git-Url: http://git.scottworley.com/inverse-tax/blobdiff_plain/49188cbe174f6f0559037bb2f6e51300dac90a85..d0678fe5d5c229220e1b4e7e7cbd470b157c3261:/tax.js?ds=inline diff --git a/tax.js b/tax.js index d9bd34c..f3d2406 100644 --- a/tax.js +++ b/tax.js @@ -61,7 +61,7 @@ function invert(table) { // and the calculate the inverse's bounds const ms = table.map(([start, end, rate]) => 1 - rate); - const full_brackets = [[0]].concat(table.map(([start, end, rate]) => (end - start) * rate)).slice(0, table.length); + const full_brackets = [0].concat(table.map(([start, end, rate]) => (end - start) * rate)).slice(0, table.length); function sum_lower_brackets(remaining_brackets, acc = 0) { if (remaining_brackets.length == 0) return []; return [acc + remaining_brackets[0]].concat(sum_lower_brackets(remaining_brackets.slice(1), acc + remaining_brackets[0])); @@ -80,11 +80,11 @@ function invert(table) { const inverse_table = table.map(([start, end, rate], i) => { const m = ms[i]; const b = bs[i]; - return [(start - b) / m, (end - b) / m, m, b]; + return [m * start + b, m * end + b, m, b]; }); return function(net) { for (const [start, end, m, b] of inverse_table) { - if (start < net && net < end) { + if (start <= net && net <= end) { return (net - b) / m; } }