Question

I have the following code grabbing a JSON object from github and I am tring to add certain parts to an array.

function getTree(hash) {
    var pathToTree, returnedJSON;
    pathToTree = 'https://api.github.com/repos/myaccount/myrepo/git/trees/' + hash;
    $.ajax({
        accepts: 'application/vnd.github-blob.raw',
        dataType: 'jsonp',
        url: pathToTree,
        success: function (json) {
            returnedJSON = json;
        },
        error: function (error) {
            console.debug(error);
        }
    });
    return returnedJSON;
}

function parseTree(hash) {
    var objectedJSON, objectList = [], i, entry;
    objectedJSON = getTree(hash, function () {
        console.debug(objectedJSON);                    // this is not appearing in console
        for (i = 0;  i < objectedJSON.data.tree.length; i += 1) {
            entry = objectedJSON.data.tree[i];
            console.debug(entry);
            if (entry.type === 'blob') {
                if (entry.type.slice(-4) === '.svg') {     // we only want the svg images not the ignore file and README etc
                    objectList.append(i.content);
                }
            } else if (entry.type === 'tree') {
                    objectList.append(parseTree(getTree(entry.sha)));
            }
        }

    });
    return objectList;
}

$(document).ready(function () {
    var objects = parseTree('master', function () {
        console.debug(objects);
    });
});

I have the code retrieving the JSON object fine but I run into trouble when trying to get it parsed (aka pulling out the bits I want). The callbacks I am using do not seem to be going and was wondering if someone could look it over and help me out.

Specifically, can I add a callback to any function I choose? Do I have to do anything to that function?

Answer 1

I have fixed the code to illustrate how you would go about it.

function getTree(hash, cb) {
    // notice that I copy the callback and hash references to have access to them in this 
    // function's closure and any subsequent closures, like the success and error
    // callbacks.
    var pathToTree, returnedJSON, cb = cb, hash = hash;
    pathToTree = 'https://api.github.com/repos/myaccount/myrepo/git/trees/' + hash;
    $.ajax({
        accepts: 'application/vnd.github-blob.raw',
        dataType: 'jsonp',
        url: pathToTree,
        success: function (json) {
            returnedJSON = json;
            // if anything was passed, call it.
            if (cb) cb(json);
        },
        error: function (error) {
            console.debug(error);
            // an error happened, check it out.
            throw error;
        }
    });
    return returnedJSON;
}

function parseTree(hash) {
    var objectedJSON, objectList = [], i, entry;
    objectedJSON = getTree(hash, function (objectedJSON) {
        console.debug(objectedJSON);                    // this is not appearing in console
        for (i = 0;  i < objectedJSON.data.tree.length; i += 1) {
            entry = objectedJSON.data.tree[i];
            console.debug(entry);
            if (entry.type === 'blob') {
                if (entry.type.slice(-4) === '.svg') {     // we only want the svg images not the ignore file and README etc
                    objectList.append(i.content);
                }
            } else if (entry.type === 'tree') {
                    objectList.append(parseTree(getTree(entry.sha)));
            }
        }

    });
    return objectList;
}

$(document).ready(function () {
    var objects = parseTree('master', function () {
        console.debug(objects);
    });
});