first commit

.gitignore

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+node_modules

index.js

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+const testFunction = (test) => {
+  return test
+}
+
+const getHtmlDiff = (base, compare) => {
+
+  const baseText = textClean(base)
+  const compareText = textClean(compare)
+  const baseTextArray = getTextArray(baseText)
+  const compareTextArray = getTextArray(compareText)
+  const baseNGramArrayArray = getNGramArrayArray(baseTextArray) // array with an index for each word [0,1,2...] in base text and each index has an array of ngrams it is a part of
+  const baseNGramMap = getReverseNGramMap(baseTextArray) // a map where key is the ngram and value is array of the index positions that are included in the given array
+  const compareNGramArrayArray = getNGramArrayArray(compareTextArray) // array with an index per word in compare text and each index has an array of ngrams it is a part of
+  const compareNGramMap = getReverseNGramMap(compareTextArray) // a map where key is the ngram and value is array of the index positions that are included in the given array
+
+  return {
+    base: getHtmlArray(baseNGramArrayArray, compareNGramMap, baseTextArray, "base").join(" "),
+    compare: getHtmlArray(compareNGramArrayArray, baseNGramMap, compareTextArray, "compare").join(" "),
+  }
+}
+
+
+const getHtmlArray = (nGramArrayArray, opposingMap, textArray, baseOrCompare) => {
+  const htmlArray = nGramArrayArray.map((ngramsForWord, i) => {
+    matchingWords = []
+    //loop through each of the ngrams for a given word
+    ngramsForWord.forEach((ngram) => {
+      // find "intersection" by checking to see if compareNGramMap contains this ngram. if it does add index of the word that is a part of the given ngram
+      if (opposingMap[ngram]){
+        matchingWords.push(i)
+      }
+    })
+    const match = matchingWords.includes(i) ? " match" : ""
+    return "<seg class='" + baseOrCompare + match + "' id='" + baseOrCompare + "-" + i + "' data-target='" + baseOrCompare + "' data-index='" + i + "'>" + textArray[i] + "</seg>"
+  })
+  return htmlArray
+}
+const getTextArray = (text) => {
+  const firstTextArray = text.split(" ")
+  var textArray = firstTextArray.filter(Boolean);
+  return textArray
+
+}
+
+const getNGramArrayArray = (textArray) => {
+  const nGramSize = 4
+  const textLength = textArray.length
+  const nGramArrayArray = []
+  for (i=0; i<textLength; i++){
+    const nGramArray = []
+    for (n=0; n<nGramSize; n++){
+      if (i-n >= 0){
+      const nGramSlice = textArray.slice(i-n, (i-n)+nGramSize).join("")
+      nGramArray.push(nGramSlice)
+      }
+    }
+    nGramArrayArray.push(nGramArray)
+  }
+  return nGramArrayArray
+}
+
+const getReverseNGramMap = (textArray) => {
+  const nGramSize = 4
+  const textLength = textArray.length
+  const nGramMap = {}
+  for (i=0; i<textLength; i++){
+    const nGramArray = []
+    for (n=0; n<nGramSize; n++){
+      if (i-n >= 0){
+      const nGramSlice = textArray.slice(i-n, (i-n)+nGramSize).join("")
+      nGramArray.push(nGramSlice)
+      }
+    }
+    nGramArray.forEach((ngram) => {
+        if (nGramMap[ngram]){
+          nGramMap[ngram] = [...nGramMap[ngram], i]
+        }
+        else{
+          nGramMap[ngram] = [i]
+        }
+      })
+  }
+  return nGramMap
+}
+
+const textClean = (text) => {
+    // lowercase
+    let punctuationless = text.toLowerCase()
+    // remove most punctuation
+    punctuationless = punctuationless.replace(/[.,/#!$%^&*;:{}=\-_`~()/\u00B6/|/\u204B/]/g,"");
+    //convert v->u, ae->e, oe-e>
+    punctuationless = punctuationless.replace(/v/g, "u");
+    punctuationless = punctuationless.replace(/ae/g, "e");
+    punctuationless = punctuationless.replace(/oe/g, "e");
+    punctuationless = punctuationless.replace(/oe/g, "e");
+    punctuationless = punctuationless.replace(/y/g, "i");
+    //remove space
+    punctuationless = punctuationless.replace(/\s{2,}/g," ");
+
+    const finalFinalString = punctuationless
+    return finalFinalString
+}
+
+module.exports = {getTextArray, getHtmlArray, getHtmlDiff, testFunction, getNGramArrayArray, textClean, getReverseNGramMap}