findIndex method
The findIndex method allows
you to find the index of the first
element according to the
callback
passed in the parameter. If the
element is not found, then
-1 is returned.
Syntax
array.findIndex(function);
Example
Let's find the index of the first even array element:
let arr = [1, 2, 3, 4, 5];
let res = arr.findIndex(function (elem){
return elem % 2 == 0;
});
console.log(res);
The code execution result:
1
Example
And now let's set such conditions in the function, which will not match any element in an array:
let arr = [1, 2, 3, 4, 5];
let res = arr.findIndex(function (elem){
return elem < 0;
});
console.log(res);
The code execution result:
-1
See also
-
the
findmethod
that searches for an element in an array -
the
findLastmethod
that searches for an element from the end of an array -
the
findLastIndexmethod
that searches for the index of an element from the end of an array
