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Diffstat (limited to 'node_modules/leven/index.js')
-rw-r--r-- | node_modules/leven/index.js | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/node_modules/leven/index.js b/node_modules/leven/index.js new file mode 100644 index 000000000..bb44b7919 --- /dev/null +++ b/node_modules/leven/index.js @@ -0,0 +1,85 @@ +/* eslint-disable no-nested-ternary */ +'use strict'; +var arr = []; +var charCodeCache = []; + +module.exports = function (a, b) { + if (a === b) { + return 0; + } + + var swap = a; + + // Swapping the strings if `a` is longer than `b` so we know which one is the + // shortest & which one is the longest + if (a.length > b.length) { + a = b; + b = swap; + } + + var aLen = a.length; + var bLen = b.length; + + if (aLen === 0) { + return bLen; + } + + if (bLen === 0) { + return aLen; + } + + // 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 (aLen > 0 && (a.charCodeAt(~-aLen) === b.charCodeAt(~-bLen))) { + aLen--; + bLen--; + } + + if (aLen === 0) { + return bLen; + } + + // Performing prefix trimming + // We can linearly drop prefix common to both strings since they + // don't increase distance at all + var start = 0; + + while (start < aLen && (a.charCodeAt(start) === b.charCodeAt(start))) { + start++; + } + + aLen -= start; + bLen -= start; + + if (aLen === 0) { + return bLen; + } + + var bCharCode; + var ret; + var tmp; + var tmp2; + var i = 0; + var j = 0; + + while (i < aLen) { + charCodeCache[start + i] = a.charCodeAt(start + i); + arr[i] = ++i; + } + + while (j < bLen) { + bCharCode = b.charCodeAt(start + j); + tmp = j++; + ret = j; + + for (i = 0; i < aLen; i++) { + tmp2 = bCharCode === charCodeCache[start + i] ? tmp : tmp + 1; + tmp = arr[i]; + ret = arr[i] = tmp > ret ? tmp2 > ret ? ret + 1 : tmp2 : tmp2 > tmp ? tmp + 1 : tmp2; + } + } + + return ret; +}; |