Appending conditions in a numerical loop (JavaScript)

Question

I have four IF statements, is it possible to rewrite this into a neater loop, where the [i] may be '4' or higher.

if (typed.length == 1 && c.charAt(0) == typed[0]) { 
    //something ; 
    return false;
}

if (typed.length == 2 && c.charAt(0) == typed[0] 
    && c.charAt(1) == typed[1]) {  
    //something ; 
    return false;
}

if (typed.length == 3 && c.charAt(0) == typed[0] 
    && c.charAt(1) == typed[1] && c.charAt(2) == typed[2]) {  
    //something ; 
    return false;
}

if (typed.length == 4 && c.charAt(0) == typed[0] 
    && c.charAt(1) == typed[1] && c.charAt(2) == typed[2] 
    && c.charAt(3) == typed[3]) {  
    //something ; 
    return false;
}

is the order of c and typed always the same, or can c contain a randomly set characters that may be contained in typed? — Yanick Rochon
– Yanick Rochon, Commented Feb 7, 2011 at 4:00

deceze · Accepted Answer · 2011-02-07 03:58:37Z

3

Looks to me like something like this should to it:

if (c.substr(0, typed.length) == typed)

Possibly typed.join() if typed is an array.

answered Feb 7, 2011 at 3:58

deceze♦

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8 Comments

Jason Over a year ago

I agree with this method, but Brandon was asking specifically for a loop.

deceze Over a year ago

@Yanick I have to assume a lot about this question, since there's little info... :)

deceze Over a year ago

@Jason The OP doesn't necessarily always know what he wants... ;)

codeandcloud Over a year ago

@+1: beat me to it! because the question can be simplified as checked whether "typed" is same as a predefined "c"

bcm Over a year ago

brilliant! thanks, I don't need the loop anymore with your solution.

|

Jason · Accepted Answer · 2011-02-07 03:57:20Z

1

Try this

for(var x=0; x<typed.length; x++)
{
   if(c.chatAt(x)!=typed[x]) { return false; }
}
return true;

answered Feb 7, 2011 at 3:57

Jason

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Comments

Phrogz · Accepted Answer · 2011-02-07 04:00:31Z

0

for (var i=1; i<=4; ++i){
  if (typed.length!=i) continue;
  var OK = true;
  for (var j=0;j<i;++j){
    OK = OK && (c.charAt(0)==typed[j]);
  }
  if (OK){
    // something
    return false;
  }
}

answered Feb 7, 2011 at 4:00

Phrogz

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Comments

Yanick Rochon · Accepted Answer · 2011-02-07 04:05:18Z

0

Forget about two nested loops, or assuming c and typed are "ordered", just look for the char in c

for (var i=0; i<typed.length; i++) {
   if (c.indexOf(typed.charAt(i)) >= 0) {  // or c.indexOf(typed.charAt(i)) == i
      return false;
   }
}
return true;

answered Feb 7, 2011 at 4:05

Yanick Rochon

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