21 lines
861 B
TypeScript
21 lines
861 B
TypeScript
export function convertBase({ value, fromBase, toBase }: { value: string; fromBase: number; toBase: number }) {
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const range = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/'.split('');
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const fromRange = range.slice(0, fromBase);
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const toRange = range.slice(0, toBase);
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let decValue = value
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.split('')
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.reverse()
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.reduce((carry: bigint, digit: string, index: number) => {
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if (!fromRange.includes(digit)) {
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throw new Error(`Invalid digit "${digit}" for base ${fromBase}.`);
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}
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return (carry += BigInt(fromRange.indexOf(digit)) * BigInt(fromBase) ** BigInt(index));
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}, 0n);
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let newValue = '';
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while (decValue > 0) {
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newValue = toRange[Number(decValue % BigInt(toBase))] + newValue;
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decValue = (decValue - (decValue % BigInt(toBase))) / BigInt(toBase);
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}
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return newValue || '0';
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}
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