I’ve edited your code for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.
In your reduce callback, you are hoping to add to numbers. The problem is, in Javascript, when the + operator is used between a string and a number, the number gets coerced into a string, so the + and the two strings are concatenated together. You will need to convert the string into a number to be able to add the two numbers together.
Just to be clear, your myArray is an array of string characters and not an array of numbers.