Check if the elements in array have been connected into a pair in Javascript -

i have problem can't seem solve, maybe can help.

there array have. e.g. ['@dog','@cat','@mouse']

i want reiterate through each value in array , connect other values in same array (through building db query).

however, because i'll writing in database need avoid duplicates.

so if @cat has been connected @mouse time for statement reaches @mouse want skip adding connection @cat (and @dog because connected on first iteration @mouse.

i've been trying for loops, such

for (var i=0; i<animals.length; i++) {     (var j = 0; j<animals.length; j++) {         if (animals[i] !== animals[j]) {             // adds connection between animals[i] , animals[j]         }     } } 

but what's best way implement check of existing pairs? (where doesn't matter element first, second - e.g. graph not unidirectional).

this becomes problem if i'm going have more 4 elements in array...

thank help!

for (var i=0; i<animals.length; i++) {     (var j = 0; j<i; j++) {         if (animals[i] !== animals[j]) {             // adds connection between animals[i] , animals[j]         }     } } 

this way, each element of array compared against before in array. think closer want.