Found the problem
Lines like:
for (let i = 0; i < chunks.length - 1; i++) {
Not good when you remove the ;.
AI can explain this as well:
In JavaScript, you can omit semicolons ; at the end of statements in many cases due to a feature called Automatic Semicolon Insertion (ASI). However, semicolons cannot be omitted everywhere without risk of causing errors or unexpected behavior. Generally, semicolons can be omitted when:
- Statements are on separate lines.
- The next line does not start with
(,[,+,-,/, or other tokens that can cause ambiguity.- When a statement ends before a line break that is correctly interpreted by the JavaScript engine.
Common cases where semicolons can be safely omitted include after variable declarations, simple expressions, return statements followed by line breaks, and standalone statements that do not directly concatenate or chain onto the next line.
But semicolons are needed or recommended to avoid errors in situations like:
- When two statements are placed on the same line.
- When a line starts with
(or[which could be interpreted as a continuation of the previous statement.- To explicitly terminate statements that precede control structures like loops or function calls.
Because of these nuances, many developers prefer to always use semicolons explicitly to avoid unintended bugs.
In summary, semicolons can often be omitted due to Automatic Semicolon Insertion, but careful attention to code structure and line breaks is necessary to avoid errors.
The AI response is correct but overly complex. 
In reality, you can safely ignore ; except where you have >1 statement on a line or in the singular exception that JS might interpret an IIFE as a continuation (prefix the IIFE with ; if you want to be absolutely sure - but it is a very rare exception).
Yes, which I mentioned. for loops are one of the very few places in JS that you typically have >1 statement on a single line.
And I agree.
I am (still) not competent enough to see those and put back the ; if in such a line.
I'll have to work on that. But I guess if I originally ask for no trailing ; then all is good.
I may need to log in so I can set this as an ongoing preference.
for (let i = 0; i < chunks.length - 1; i++) {
This really is a legacy format. Used in JS because it is familiar to users of other languages. All you really need to think is that each of the bits separated by ; are different lines of code passed to the for statement. If the for statement were a function like other js functions, it might look something like this:
/** loop
* @param {number} start Starting increment
* @param {number} max Max increment
* @param {number} increment Step to increment by
* @param {function} run Code to run for each increment
*/
for(0, chunks.length - 1, 1, (i) => {
...
})
