1var assert = require('assert');
2
3function detectSubstring(str, subStr) {
4  let idxOfStart = 0,
5    j = 0;
6
7  for (i = 0; i < str.length; i++) {
8    // if match, compare next character of subStr with next of string
9    if (str[i] == subStr[j]) {
10      j++;
11      if (j == subStr.length) {
12        return i - (subStr.length - 1);
13      }
14    } else {
15      i -= j;
16      j = 0;
17    }
18  }
19
20  return -1;
21}
22
23// console.log(detectSubstring('ggraph', 'graph'));
24// console.log(detectSubstring('geography', 'graph'));
25// console.log(detectSubstring('digginn', 'inn'));
26
27try {
28  assert.equal(detectSubstring('thepigflewwow', 'flew'), 6);
29
30  console.log(
31    'PASSED: ' + "`detectSubstring('thepigflewwow', 'flew')` should return `6`"
32  );
33} catch (err) {
34  console.log(err);
35}
36
37try {
38  assert.equal(detectSubstring('twocanplay', 'two'), 0);
39
40  console.log(
41    'PASSED: ' + "`detectSubstring('twocanplay', 'two')` should return `0`"
42  );
43} catch (err) {
44  console.log(err);
45}
46
47try {
48  assert.equal(detectSubstring('wherearemyshorts', 'pork'), -1);
49
50  console.log(
51    'PASSED: ' +
52      "`detectSubstring('wherearemyshorts', 'pork')` should return `-1`"
53  );
54} catch (err) {
55  console.log(err);
56}