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All topics›JavaScript›String algorithms

Implement indexOf (strStr)

intermediatelayer A7 · String algorithms5 tests

Write strStr(haystack, needle) returning the index of the first occurrence of needle inside haystack, or -1 when it does not occur.

  • An empty needle matches at index 0
  • Matches may overlap earlier partial matches, so a failed comparison must not skip characters blindly
  • Do not call the built-in indexOf, includes or search

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