diff options
Diffstat (limited to 'alarm/node_modules/graphql/jsutils/suggestionList.js.flow')
-rw-r--r-- | alarm/node_modules/graphql/jsutils/suggestionList.js.flow | 138 |
1 files changed, 0 insertions, 138 deletions
diff --git a/alarm/node_modules/graphql/jsutils/suggestionList.js.flow b/alarm/node_modules/graphql/jsutils/suggestionList.js.flow deleted file mode 100644 index 017e779..0000000 --- a/alarm/node_modules/graphql/jsutils/suggestionList.js.flow +++ /dev/null @@ -1,138 +0,0 @@ -// @flow strict -import naturalCompare from './naturalCompare'; - -/** - * Given an invalid input string and a list of valid options, returns a filtered - * list of valid options sorted based on their similarity with the input. - */ -export default function suggestionList( - input: string, - options: $ReadOnlyArray<string>, -): Array<string> { - const optionsByDistance = Object.create(null); - const lexicalDistance = new LexicalDistance(input); - - const threshold = Math.floor(input.length * 0.4) + 1; - for (const option of options) { - const distance = lexicalDistance.measure(option, threshold); - if (distance !== undefined) { - optionsByDistance[option] = distance; - } - } - - return Object.keys(optionsByDistance).sort((a, b) => { - const distanceDiff = optionsByDistance[a] - optionsByDistance[b]; - return distanceDiff !== 0 ? distanceDiff : naturalCompare(a, b); - }); -} - -/** - * Computes the lexical distance between strings A and B. - * - * The "distance" between two strings is given by counting the minimum number - * of edits needed to transform string A into string B. An edit can be an - * insertion, deletion, or substitution of a single character, or a swap of two - * adjacent characters. - * - * Includes a custom alteration from Damerau-Levenshtein to treat case changes - * as a single edit which helps identify mis-cased values with an edit distance - * of 1. - * - * This distance can be useful for detecting typos in input or sorting - */ -class LexicalDistance { - _input: string; - _inputLowerCase: string; - _inputArray: Array<number>; - _rows: [Array<number>, Array<number>, Array<number>]; - - constructor(input: string) { - this._input = input; - this._inputLowerCase = input.toLowerCase(); - this._inputArray = stringToArray(this._inputLowerCase); - - this._rows = [ - new Array(input.length + 1).fill(0), - new Array(input.length + 1).fill(0), - new Array(input.length + 1).fill(0), - ]; - } - - measure(option: string, threshold: number): number | void { - if (this._input === option) { - return 0; - } - - const optionLowerCase = option.toLowerCase(); - - // Any case change counts as a single edit - if (this._inputLowerCase === optionLowerCase) { - return 1; - } - - let a = stringToArray(optionLowerCase); - let b = this._inputArray; - - if (a.length < b.length) { - const tmp = a; - a = b; - b = tmp; - } - const aLength = a.length; - const bLength = b.length; - - if (aLength - bLength > threshold) { - return undefined; - } - - const rows = this._rows; - for (let j = 0; j <= bLength; j++) { - rows[0][j] = j; - } - - for (let i = 1; i <= aLength; i++) { - const upRow = rows[(i - 1) % 3]; - const currentRow = rows[i % 3]; - - let smallestCell = (currentRow[0] = i); - for (let j = 1; j <= bLength; j++) { - const cost = a[i - 1] === b[j - 1] ? 0 : 1; - - let currentCell = Math.min( - upRow[j] + 1, // delete - currentRow[j - 1] + 1, // insert - upRow[j - 1] + cost, // substitute - ); - - if (i > 1 && j > 1 && a[i - 1] === b[j - 2] && a[i - 2] === b[j - 1]) { - // transposition - const doubleDiagonalCell = rows[(i - 2) % 3][j - 2]; - currentCell = Math.min(currentCell, doubleDiagonalCell + 1); - } - - if (currentCell < smallestCell) { - smallestCell = currentCell; - } - - currentRow[j] = currentCell; - } - - // Early exit, since distance can't go smaller than smallest element of the previous row. - if (smallestCell > threshold) { - return undefined; - } - } - - const distance = rows[aLength % 3][bLength]; - return distance <= threshold ? distance : undefined; - } -} - -function stringToArray(str: string): Array<number> { - const strLength = str.length; - const array = new Array(strLength); - for (let i = 0; i < strLength; ++i) { - array[i] = str.charCodeAt(i); - } - return array; -} |