Sha256: d6ca836b495843944a1b31b11574f5997bd6ca2c79269d277ca45383b4d68d60
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Size: 1.26 KB
Versions: 19
Compression:
Stored size: 1.26 KB
Contents
var makeString = require('./helper/makeString');
/**
* Based on the implementation here: https://github.com/hiddentao/fast-levenshtein
*/
module.exports = function levenshtein(str1, str2) {
'use strict';
str1 = makeString(str1);
str2 = makeString(str2);
// Short cut cases
if (str1 === str2) return 0;
if (!str1 || !str2) return Math.max(str1.length, str2.length);
// two rows
var prevRow = new Array(str2.length + 1);
// initialise previous row
for (var i = 0; i < prevRow.length; ++i) {
prevRow[i] = i;
}
// calculate current row distance from previous row
for (i = 0; i < str1.length; ++i) {
var nextCol = i + 1;
for (var j = 0; j < str2.length; ++j) {
var curCol = nextCol;
// substution
nextCol = prevRow[j] + ( (str1.charAt(i) === str2.charAt(j)) ? 0 : 1 );
// insertion
var tmp = curCol + 1;
if (nextCol > tmp) {
nextCol = tmp;
}
// deletion
tmp = prevRow[j + 1] + 1;
if (nextCol > tmp) {
nextCol = tmp;
}
// copy current col value into previous (in preparation for next iteration)
prevRow[j] = curCol;
}
// copy last col value into previous (in preparation for next iteration)
prevRow[j] = nextCol;
}
return nextCol;
};
Version data entries
19 entries across 19 versions & 1 rubygems