javascript - Why `pattern.test(name)` opposite results on consecutive calls -

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• why regexp global flag give wrong results? 5 answers

why code returning first true, false

var pattern = new regexp("mstea", 'gi'), name = "amanda olmstead";  console.log('1', pattern.test(name)); console.log('1', pattern.test(name)); 

demo: fiddle

g repeating searches. changes regular expression object iterator. if want use test function check string valid according pattern, remove modifier :

var pattern = new regexp("mstea", 'i'), name = "amanda olmstead"; 

the test function, contrary replace or match doesn't consume whole iteration, lets in "bad" state. should never use modifier when using test function.