grading
Version:
Grading of student submissions, in particular programming tests.
95 lines • 3.31 kB
JavaScript
;
// cfrom https://github.com/tj/commander.js/blob/master/lib/suggestSimilar.js
Object.defineProperty(exports, "__esModule", { value: true });
exports.suggestSimilar = void 0;
const maxDistance = 3;
function editDistance(a, b) {
// https://en.wikipedia.org/wiki/Damerau–Levenshtein_distance
// Calculating optimal string alignment distance, no substring is edited more than once.
// (Simple implementation.)
// Quick early exit, return worst case.
if (Math.abs(a.length - b.length) > maxDistance)
return Math.max(a.length, b.length);
// distance between prefix substrings of a and b
const d = [];
// pure deletions turn a into empty string
for (let i = 0; i <= a.length; i++) {
d[i] = [i];
}
// pure insertions turn empty string into b
for (let j = 0; j <= b.length; j++) {
d[0][j] = j;
}
// fill matrix
for (let j = 1; j <= b.length; j++) {
for (let i = 1; i <= a.length; i++) {
let cost = 1;
if (a[i - 1] === b[j - 1]) {
cost = 0;
}
else {
cost = 1;
}
d[i][j] = Math.min(d[i - 1][j] + 1, // deletion
d[i][j - 1] + 1, // insertion
d[i - 1][j - 1] + cost // substitution
);
// transposition
if (i > 1 && j > 1 && a[i - 1] === b[j - 2] && a[i - 2] === b[j - 1]) {
d[i][j] = Math.min(d[i][j], d[i - 2][j - 2] + 1);
}
}
}
return d[a.length][b.length];
}
/**
* Find close matches, restricted to same number of edits.
*
* @param {string} word
* @param {string[]} candidates
* @returns {string}
*/
function suggestSimilar(word, candidates) {
if (!candidates || candidates.length === 0)
return '';
// remove possible duplicates
candidates = Array.from(new Set(candidates));
const searchingOptions = word.startsWith('--');
if (searchingOptions) {
word = word.slice(2);
candidates = candidates.map(candidate => candidate.slice(2));
}
let similar = [];
let bestDistance = maxDistance;
const minSimilarity = 0.4;
candidates.forEach((candidate) => {
if (candidate.length <= 1)
return; // no one character guesses
const distance = editDistance(word, candidate);
const length = Math.max(word.length, candidate.length);
const similarity = (length - distance) / length;
if (similarity > minSimilarity) {
if (distance < bestDistance) {
// better edit distance, throw away previous worse matches
bestDistance = distance;
similar = [candidate];
}
else if (distance === bestDistance) {
similar.push(candidate);
}
}
});
similar.sort((a, b) => a.localeCompare(b));
if (searchingOptions) {
similar = similar.map(candidate => `--${candidate}`);
}
if (similar.length > 1) {
return `\n (Did you mean one of "${similar.join('", "')}"?)`;
}
if (similar.length === 1) {
return `\n (Did you mean "${similar[0]}"?)`;
}
return '';
}
exports.suggestSimilar = suggestSimilar;
//# sourceMappingURL=suggestSimilar.js.map