js foreach 不能中断的现象及理解

var testArray = [1, 2, 3, 4, 5];
testArray.forEach(element => {
    if (element == 3) {
        return;
    }
    console.log(element);
});

1
2
4
5

There is no way to stop or break a forEach() loop other than by throwing an exception. 
If you need such behavior, the forEach() method is the wrong tool.

Early termination may be accomplished with:

A simple for loop
A for...of / for...in loops
Array.prototype.every()
Array.prototype.some()
Array.prototype.find()
Array.prototype.findIndex()
Array methods: every(), some(), find(), and findIndex() test the array elements with a predicate returning a truthy value to determine if further iteration is required.