52 lines
1.5 KiB
Plaintext
52 lines
1.5 KiB
Plaintext
import { distance } from 'fastest-levenshtein'
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import { RankedDictionary } from '../types'
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const getUsedThreshold = (
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password: string,
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entry: string,
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threshold: number,
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) => {
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const isPasswordToShort = password.length <= entry.length
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const isThresholdLongerThanPassword = password.length <= threshold
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const shouldUsePasswordLength =
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isPasswordToShort || isThresholdLongerThanPassword
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// if password is too small use the password length divided by 4 while the threshold needs to be at least 1
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return shouldUsePasswordLength ? Math.ceil(password.length / 4) : threshold
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}
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export interface FindLevenshteinDistanceResult {
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levenshteinDistance: number
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levenshteinDistanceEntry: string
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}
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const findLevenshteinDistance = (
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password: string,
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rankedDictionary: RankedDictionary,
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threshold: number,
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): Partial<FindLevenshteinDistanceResult> => {
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let foundDistance = 0
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const found = Object.keys(rankedDictionary).find((entry) => {
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const usedThreshold = getUsedThreshold(password, entry, threshold)
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if (Math.abs(password.length - entry.length) > usedThreshold) {
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return false
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}
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const foundEntryDistance = distance(password, entry)
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const isInThreshold = foundEntryDistance <= usedThreshold
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if (isInThreshold) {
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foundDistance = foundEntryDistance
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}
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return isInThreshold
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})
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if (found) {
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return {
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levenshteinDistance: foundDistance,
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levenshteinDistanceEntry: found,
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}
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}
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return {}
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}
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export default findLevenshteinDistance
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