Javascript check if first element of tuple exists in array of tuples

Question

I have an array of tuples, where first element of tuple is string and second is int. Every tuple has array structure:

var array = [["ele1",1], ["ele2",1], ["ele3",1], ["ele4",1]];

How can I easily check if a string is element of a tuple in array of tuples in javascript?

if array.contains(tuple with first element "ele2")

Is it possible to do it without for loop (checking each element of array)?

codebox · Accepted Answer · 2021-11-30 13:58:48Z

8

If you are using a relatively modern browser you can just do this:

array.some(function(a) {
    return a[0] === 'string that you want';
})

or, more compactly:

array.some(a => a[0] === 'string that you want')

answered Oct 31, 2014 at 11:48

codebox

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Comments

Nikhil Baliga · Accepted Answer · 2014-10-31 11:54:27Z

1

Might seem like a hack but still... :)

array.toString().split(',').indexOf('ele2') % 2 == 0

answered Oct 31, 2014 at 11:54

Nikhil Baliga

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Jared Smith · Accepted Answer · 2014-10-31 11:50:00Z

0

There isn't an 'easy way'. You will have to iterate through the array and do a check on every element:

var i = array.length, foo;
while (i--) {
   foo = array[i];
   if (foo[0] == 'ele2') {
       break; //success!
   }
}

Or the functional equivalent in the other answer.

answered Oct 31, 2014 at 11:50

Jared Smith

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