Util Sails Service with PopulateDeep function

useDeepPopulate.js

User.find(id).populate('preferences').exec(function (err, user) {
    if(err) {
        sails.log.error("ERR:", err);
    }
    sails.services['util'].populateDeep('user', user[0], 'preferences.nestedPreferences', function (err, newUser) {
        if (err) {
            sails.log.error("ERR:", err);
        }
        console.log(newUser);
    });

});

util.js

/**
 * Created by dinana on 25/4/15.
 * Please keep credits for re-use.
 */

function populateDeep2(parentModelName, parentModel, path, cb) {
    if( !path || path.length == 0 ) {
        cb("No path given");
        return;
    }
    var count = 0;
    var parent = JSON.parse(JSON.stringify(parentModel));
    populateDeepInner(parentModelName, parent, path, cb);
    function populateDeepInner(parentModelName, parentInstance, path, cb) {
        if(Array.isArray(parentInstance)) {
            count = count + parentInstance.length;
            parentInstance.map(function(value, index, origArray){
                handle(value)
            })
        } else {
            count++;
            handle(parentInstance)
        }

        function handle(parentInstance) {
            var pathArray = path.split('.');
            var childInstance = parentInstance[pathArray[0]]
            if (isPopulated(childInstance)) {
                doneIfDone(childInstance, pathArray);
            } else {
                var childAssociation = getChildModel(parentModelName, pathArray[0]);
                var findCriteria;
                switch (childAssociation.type) {
                    case 'model':
                        findCriteria = childInstance;
                        break;
                    case 'collection':
                        findCriteria = {};
                        findCriteria[childAssociation.via] = parentInstance.id;
                        break;
                }
                if(pathArray.length > 1) {
                    childAssociation.model.find(findCriteria)
                        .populate(pathArray[1]).exec(function (err, populatedChild) {
                            if(err) {
                                console.log("Error:",err)
                                cb(err)
                            }
//                            pathArray.splice(0,1)
                            stitcher(populatedChild);
                        })
                } else {
                    childAssociation.model.find(findCriteria)
                        .exec(function (err, populatedChild) {
                            if(err) {
                                console.log("Error:",err)
                                cb(err)
                            }
//                            pathArray.splice(0,1)
                            stitcher(populatedChild);
                        })
                }
            }
            function stitcher(newChildInstance) {
                newChildInstance = JSON.parse(JSON.stringify(newChildInstance));
                switch(getChildModel(parentModelName,pathArray[0]).type) {
                    case 'model':
                        parentInstance[pathArray[0]] = newChildInstance[0];
                        break;
                    case 'collection':
                        parentInstance[pathArray[0]] = newChildInstance;
                        break;
                }
                doneIfDone(newChildInstance)
            }
            // Assumptions: newChild is already populated
            function doneIfDone(newChildInstance) {
                if(pathArray.length > 1) {
                    var newPathArray = pathArray.slice(1)
                    var newPath = newPathArray.join('.');
                    count--;
                    populateDeepInner(getChildModel(parentModelName, pathArray[0]).modelName, newChildInstance, newPath, cb);
                } else {
                    count--;
                    if (count == 0)
                        cb(null, parent);
                }
            }
            function getChildModel(parentModelName, childModelName) {
                var childAssociation = sails.models[parentModelName.toLowerCase()].associations.filter(function (value) {
                    return value.alias == childModelName;
                })
                return {model:sails.models[childAssociation[0][childAssociation[0].type]], type:childAssociation[0].type, via: childAssociation[0].via, modelName:childAssociation[0][childAssociation[0].type]};
            }
        }
        function isPopulated(model) {
            return (model && typeof model != 'string')
        }
    }
}
 module.exports = {populateDeep:populateDeep2}

I can't quite get this to work (the nested populate doesn't occur, and only the first populate is returned). Are there certain conditions under which this service function will not run?

When I try a double-nested populate, I receive the following error:

C:\Users\*\Documents\GitHub\*\api\services\NestedPopulateService.js:93
  return {model:sails.models[childAssociation[0][childAssociation[0].type]], t
                                                                    ^
TypeError: Cannot read property 'type' of undefined
    at getChildModel (C:\Users\*\Documents\GitHub\*\api\services\NestedPopulateService.js:93:83)

Line 93 is the following:

return {model:sails.models[childAssociation[0][childAssociation[0].type]], type:childAssociation[0].type, via: childAssociation[0].via, modelName:childAssociation[0][childAssociation[0].type]};

This is such an in-demand function, I think a few lines of comments/examples would help out a lot.

Could you please post your Models ? Thanks !

Hi , @dinana This is awesome since we have it in service we can reuse it in all controller. Thanks for the great work.

One Doubt say that we have more than one path i.e, like preferences.nestedPreferences1 or preferences1.nestedPreferences with the above model how can we pass the query

Thanks

This has stopped working for me. Any idea why?

Edit: seems like this only works with mongoDB.