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Diffstat (limited to 'node_modules/leven/index.js')
-rw-r--r-- | node_modules/leven/index.js | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/node_modules/leven/index.js b/node_modules/leven/index.js new file mode 100644 index 0000000..25f5a3d --- /dev/null +++ b/node_modules/leven/index.js @@ -0,0 +1,77 @@ +'use strict'; +const array = []; +const charCodeCache = []; + +const leven = (left, right) => { + if (left === right) { + return 0; + } + + const swap = left; + + // Swapping the strings if `a` is longer than `b` so we know which one is the + // shortest & which one is the longest + if (left.length > right.length) { + left = right; + right = swap; + } + + let leftLength = left.length; + let rightLength = right.length; + + // Performing suffix trimming: + // We can linearly drop suffix common to both strings since they + // don't increase distance at all + // Note: `~-` is the bitwise way to perform a `- 1` operation + while (leftLength > 0 && (left.charCodeAt(~-leftLength) === right.charCodeAt(~-rightLength))) { + leftLength--; + rightLength--; + } + + // Performing prefix trimming + // We can linearly drop prefix common to both strings since they + // don't increase distance at all + let start = 0; + + while (start < leftLength && (left.charCodeAt(start) === right.charCodeAt(start))) { + start++; + } + + leftLength -= start; + rightLength -= start; + + if (leftLength === 0) { + return rightLength; + } + + let bCharCode; + let result; + let temp; + let temp2; + let i = 0; + let j = 0; + + while (i < leftLength) { + charCodeCache[i] = left.charCodeAt(start + i); + array[i] = ++i; + } + + while (j < rightLength) { + bCharCode = right.charCodeAt(start + j); + temp = j++; + result = j; + + for (i = 0; i < leftLength; i++) { + temp2 = bCharCode === charCodeCache[i] ? temp : temp + 1; + temp = array[i]; + // eslint-disable-next-line no-multi-assign + result = array[i] = temp > result ? temp2 > result ? result + 1 : temp2 : temp2 > temp ? temp + 1 : temp2; + } + } + + return result; +}; + +module.exports = leven; +// TODO: Remove this for the next major release +module.exports.default = leven; |