Keep directive prologues at top of function

[TiddoLangerak]

Consider the following simple function:

function* foo() {
    "myPrologue";

    bar();
    return;
}

Transforming this with regenerator gives:

var marked0$0 = [foo].map(regeneratorRuntime.mark);
function foo() {
    return regeneratorRuntime.wrap(function foo$(context$1$0) {
        while (1) switch (context$1$0.prev = context$1$0.next) {
        case 0:
            'myPrologue';
            return context$1$0.abrupt("return", bar());
        case 2:
        case "end":
            return context$1$0.stop();
        }
    }, marked0$0[0], this);
}

However, this breaks the prologue since it's no longer at the top of the function. I think the directives should instead be kept at the top of the function:

var marked0$0 = [foo].map(regeneratorRuntime.mark);
function foo() {
    'myPrologue';
    return regeneratorRuntime.wrap(function foo$(context$1$0) {
        while (1) switch (context$1$0.prev = context$1$0.next) {
        case 0:
            return context$1$0.abrupt("return", bar());
        case 2:
        case "end":
            return context$1$0.stop();
        }
    }, marked0$0[0], this);
}

Some pre-processors, like ng-annotate, make use of directive prologues to work properly, but this is currently incompatible with regenerator.

[benjamn]

Why not keep them at the top of the foo function? That's where any variables will be declared, in case that's relevant.

[TiddoLangerak]

Yes, I think that makes most sense.