shortest-substring.js

'use strict';
var input = 'this is a test string';
input = 'aaaabbbcccdddcdbaaa';

var match = 'tist'; //accb
match = 'abc';
input = 'abcdefadfafaefd';
match = 'ef';

var matches = [];
var charbuilder = buildCharCount(match);

for (var i = 0; i < input.length; i++) {
  if (hasMatch(input.substr(i), match)) {
    matches.push(input.substr(i));
  }
}

var minSubstr;
var minSubstrIdx = 0;
var pre;
var hasMatch;
for (var i = 0; i < matches.length; i++) {
  hasMatch = false;
  var matchCharBuilder = buildCharCount(matches[i]);
  if (minSubstr === undefined) {
    hasMatch = true;
    minSubstr = matches[i].length;
    minSubstrIdx = 0;
  } else {
    Object.keys(charbuilder.charMap).forEach(function forEach(key) {
      if (matchCharBuilder.charMap[key] && matchCharBuilder.charMap[key] >= charbuilder.charMap[key]) {
        hasMatch = true;
      }
    });
    if (hasMatch) {
      pre = minSubstr;
      minSubstr = Math.min(minSubstr, matches[i].length);

      if (minSubstr !== pre) {
        minSubstrIdx = i;
      }
    }
  }
}

console.log('minSubstrIdx', minSubstrIdx, matches[minSubstrIdx]);

function hasMatch(input, target) {
  for (var i = 0; i < target.length; i++) {

    if (input.indexOf(target[i]) < 0) {
      return false;
    }
  }
  return true;
}


function buildCharCount(input) {
  var charCount = [];
  var charMap = {};

  for (var i = 0; i < input.length; i++) {
    if (charMap[input[i]]) {
      charMap[input[i]]++;
    } else {

      charMap[input[i]] = 1;
    }
  }
  var charCount = Object.keys(charMap).map(function map(item) {
    return charMap[item];
  });

  return {
    charMap: charMap,
    charCount: charCount,
    sum: function(input) {
      return charCount.reduce(function(previousValue, currentValue, currentIndex, array) {
        return previousValue + currentValue;
      });
    }
  };
}