TypeError: (fn) is not iterable when just executing a function

Question

So I have a very simple code:

// doesn't matter, just be sure that we have an array
const tasks = Array.isArray(result) ? [...result] : [result];

// works
for (let i = 0; i < tasks.length; i++) {
    this.executeNativeCommand(tasks[i].command, ...tasks[i].args);
}

// TypeError: this.executeNativeCommand is not iterable (cannot read property Symbol(Symbol.iterator))
tasks.forEach(task => {
    this.executeNativeCommand(task.command, ...task.args);
});

Also tried this['executeNativeCommand'] — it worked. What sort of magic is it?

Answer 1

The message is wrong and confusing, it should be tasks[i].args is not iterable / task.args is not iterable .

You probably ran into this V8 bug .

It was fixed three months ago (February 2020), but it seems it hasn't landed in stable node.js or Chrome yet.