I want to compare user input to a given string eg 'hello' compared 'hello' should return true that part is easy but I also want 'h', 'he', 'hel' etc to return true but not 'lo'
How would you approach this with javascript?
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2 Answers
A quick and simple way:
var match = "hello"; var test = "hel"; if( match.substr(0,test.length) == test) { // looking good! // optionally, add this to the condition: && test.length > 0 // otherwise an empty test string would match } answered Aug 9, 2014 at 14:39
Niet the Dark Absol
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4 Comments
Tesseract
That should be
match.substring(0, test.length) === test.
Niet the Dark Absol
@SpiderPig It should indeed. 's'what I get for writing PHP for several hours straight XD
Mark
any advantages / disadvantages between this solution and idans?
Niet the Dark Absol
@Ir1sh Idan's solution it much less efficient when the string doesn't match (it will try to match at every position, even though you're only interested in the start). This one is more efficient because it fails immediately.
you need to use indexOf() function.
var hello = "hello"; if(hello.indexOf("he")===0){ //its in. } 3 Comments
Tesseract
That should be
=== 0, not > 0.
Idan Magled
no, the string can be on the first position in the search string and its return 0.
Niet the Dark Absol
@IdanMagled That's what OP is asking for - a match from the start.