How to write own array method in javascript?

Question

Array.prototype.ownMethod = function(x) {
  x(this)
}

[1, 2, 3, 4].ownMethod(function(x) {
  return x[1]
}) // This callback won't work .

I tried to pass array value inside my First-class function. This method won't work for me.

You want a method to which you can pass a callback to be executed with your array ? It's not very clear — Nicolas, Apr 08 '18 at 19:40
My method can take array, inside callback function's aurgument — foysal sheykh, Apr 08 '18 at 19:47
Why not simply calling `console.log(array[1])` directly on the array instead of creating a function that takes a callback to which you pass `console.log(param[1])` it seams like code repetition to me. — Nicolas, Apr 08 '18 at 19:51
Side note: Never add to `Array.prototype` via assignment like that. [Do this instead](https://stackoverflow.com/a/22387870/157247). — T.J. Crowder, Feb 19 '22 at 13:30

score 6 · Answer 1 · answered Apr 08 '18 at 19:41

You've been caught out by Automatic Semicolon Insertion.

The function expression creates an object (the function) and the square bracket immediately after it is used as a property accessor instead of an array literal.

Add an explicit end of statement with a semi-colon to fix that.

Array.prototype.ownMethod = function(x) {
  x(this)
};

[1, 2, 3, 4].ownMethod(function(x) {
  console.log(x[1]);
})

How to write own array method in javascript?

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