JS: String.prototype.indexOf
s.indexOf(str)
s.indexOf(str, start_search_index)
Return the index where the first occurrence of first char of str, starting search at start_search_index. start_search_index by default is 0. Returns -1 if not found.
const ss = "abcabc"; // return index where first b occurs console.log ( ss.indexOf ( "b" ) ); // 1 // start at index 1 (including index 1) console.log ( ss.indexOf ( "b", 1 ) ); // 1 // start at index 2 console.log ( ss.indexOf ( "b", 2 ) ); // 4 // more than 1 char console.log ( ss.indexOf ( "bc", 2 ) ); // 4 // example of not found, returns -1 console.log ( ss.indexOf ( "xy" ) ); // -1
Reference
ECMAScript 2015 §Text Processing#sec-string.prototype.indexof
JS String
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