Do JavaScript arrays have an equivalent of Python’s “if a in list”?

Since ES6, it is recommended to use includes() instead of the clunky indexOf().

var my_array = ['a', 'b', 'c'];

my_array.includes('a');  // true

my_array.includes('dd'); // false

var my_array = ['a', 'b', 'c'];
alert(my_array.indexOf('b'));
alert(my_array.indexOf('dd'));

if element not found, you will receive -1

var IN = function(ls, val){
    return ls.indexOf(val) != -1;
}

var my_array = ['a', 'b', 'c'];
IN(my_array, 'a');

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