Why does console tell me that .filter is not a function? [closed]

Question

var str = "I am a string.";

console.log(str.split(''));

var fil = function(val){
return val !== "a";
};

console.log(str.filter(fil));

When I run this, it says the str.filter is not a function.

Answer 1

Because filter is an array function (Array.prototype.filter), while you are calling it on a string. str.split returns an array and doesn't change anything to your str. call it like console.log(str.split('').filter(fil)) and it should be fine.

Answer 2

Because you're invoking the execution of "filter" on str, which is an object without a function called "filter" of its own nor by prototype. Since filter is not present the property's value is undefined, which cannot be invoked because its type is not function.