Question

I am coding something in JS and I have to test code – I have to check if elements in 2 arrays are the same.
So I’ve got an array: boreholes = [[66000, 457000],[1111,2222]....]; and I want to check if this array contain element for eg. [66000,457000] so I did:
boreholes.indexOf([66000,457000]) but it returns -1, so I iterate trough array by:

for (var i = 0; i< boreholes.length; i++){
 if (boreholes[i] == [66000, 457000]){
  console.log('ok');
  break;
 }
};

but still I’ve got nothing. Can someone explain me what am I doing wrong?

Answer 1

You are comparing distinct objects. When comparing objects, the comparison only evaluates to true when the 2 objects being compared are the same object. I.E

var a = [1,2,3];
var b = a;
a === b //true
b = [1,2,3];
a === b //false, b is not the same object

To compare arrays like this, you need to compare all of their elements separately:

for (var i = 0; i < boreholes.length; i++) {
    if (boreholes[i][0] == 66000 && boreholes[i][1] == 457000) {
        console.log('ok');
        break;
    }
}