Question

How could I emulate the goto programming construct in this case?

$.fn.hierarchy = function(info, ret) {
    if (info.constructor !== Object) {
        info = {children: info};
        goto label1; // Illegal JavaScript
    }

    if (!info.children) {
        info.children = [];
        goto label2; // Illegal JavaScript
    }

    label1:
    if (info.children.constructor !== Array)
        info.children = [info.children];

    label2:
    /*
    // Forget this code. It's irrelevant to my specific problem
    // (which is that JS doens't allow non-nested conditionals)
    //  and caused much confusion.
    if (!info.tagc)
        info.tagc = info.tag || 'div';
    */

I know I could implement exactly ONE of these gotos as an else clause:

$.fn.hierarchy = function(info, ret) {
    if (info.constructor !== Object) {
        info = {children: info};
        //goto label1;
    }

    else if (!info.children) {
        info.children = [];
        goto label2; // Illegal JavaScript
    }

    //label1:
    if (info.children.constructor !== Array)
        info.children = [info.children];

    label2:
    /*
    // Forget this code. It's irrelevant to my specific problem
    // (which is that JS doens't allow non-nested conditionals)
    //  and caused much confusion.
    if (!info.tagc)
        info.tagc = info.tag || 'div';
    */

Or:

$.fn.hierarchy = function(info, ret) {
    if (info.constructor !== Object) {
        info = {children: info};
        goto label1; // Illegal JavaScript
    }

    if (!info.children) {
        info.children = [];
        //goto label2;
    }

    else {
        label1:
        if (info.children.constructor !== Array)
            info.children = [info.children];
    }

    //label2:
    /*
    // Forget this code. It's irrelevant to my specific problem
    // (which is that JS doens't allow non-nested conditionals)
    //  and caused much confusion.
    if (!info.tagc)
        info.tagc = info.tag || 'div';
    */

But I want to have both gotos. And, no, I don’t want additional flags.

---

EDIT:

@Luis Espinal: Your proposed solution doesn’t work. If info is {children: 'a'}, your program fails to convert info.children to [a].

$.fn.hierarchy = function(info, ret) {
    if (info.constructor !== Object) {
        info = {children: info};
        // goto label1; // Illegal JavaScript
        // label1:
        if (info.children.constructor !== Array){
            info.children = [info.children];
        }
    }
    else if (!info.children) {
        info.children = [];
        // goto label2; // Illegal JavaScript
        // label2:
        /*
        // Wrong. This has to be placed outside all of this.
        if (!info.tagc)
        {
            info.tagc = info.tag || 'div';
        }
        */
    }
    /* the following code is missing:

    else {
        // Handles the case when info.constructor === Object
        // from the beginning
        // AND
        // info.children isn't an array
        if (info.children.constructor !== Array)
            info.children = [info.children];
    }
    */

---

EDIT: Some of you seemed to think the fourth conditional is relevant to my problem. The problem is actually that I cannot do the following:

If condition1 Then action1
If !condition1 && condition2 Then action2
If !condition2 && condition3 && regardlessOf(condition1) Then action3

Without using flags (temporary boolean variables).

Basically if condition1 is true, I don’t have to test for condition2, and, if condition2 is true, I don’t have to test for condition3. But, if condition1 && !condition2, I might have to test for condition3.

Answer 1

Your function has a non planar control flow graph, and as such cannot be implemented using structured programming logic.
If you are concerned with speed, your best bet would be to duplicate label 1 and structure the code as follows:

$.fn.hierarchy = function(info, ret) {
    if (info.constructor !== Object) {
        info = {children: info};
        //goto label1; // Illegal JavaScript
        //label1:
        if (info.children.constructor !== Array)
        {info.children = [info.children];}
    }
    else{
        if (!info.children) {
            info.children = [];
            //goto label2; // Illegal JavaScript
        }
        else{
            //label1:
            if (info.children.constructor !== Array)
            {info.children = [info.children];}
        }
    }

    //label2:
    if (!info.tagc)
    {info.tagc = info.tag || 'div';}
};