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'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;
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