### levenshteinDistance

Calculates the [Levenshtein distance](https://en.wikipedia.org/wiki/Levenshtein_distance) between two strings.

Calculates the number of changes (substitutions, deletions or additions) required to convert `string1` to `string2`. 
Can also be used to compare two strings as shown in the second example.

``` js
const levenshteinDistance = (string1, string2) => {
  if (string1.length === 0) return string2.length;
  if (string2.length === 0) return string1.length;
  let matrix = Array(string2.length + 1)
    .fill(0)
    .map((x, i) => [i]);
  matrix[0] = Array(string1.length + 1)
    .fill(0)
    .map((x, i) => i);
  for (let i = 1; i <= string2.length; i++) {
    for (let j = 1; j <= string1.length; j++) {
      if (string2[i - 1] === string1[j - 1]) {
        matrix[i][j] = matrix[i - 1][j - 1];
      } else {
        matrix[i][j] = Math.min(
          matrix[i - 1][j - 1] + 1,
          matrix[i][j - 1] + 1,
          matrix[i - 1][j] + 1
        );
      }
    }
  }
  return matrix[string2.length][string1.length];
};
```

```js
levenshteinDistance('30-seconds-of-code','30-seconds-of-python-code'); // 7
const compareStrings = (string1,string2) => (100 - levenshteinDistance(string1,string2) / Math.max(string1.length,string2.length));
compareStrings('30-seconds-of-code', '30-seconds-of-python-code'); // 99.72 (%)
```