HTTP PATCH semantics with mongoose sub-documents

Question

HTTP PATCH semantics with mongoose sub-documents

I have a Map document with a number of Layer sub-documents and want to implement HTTP PATCH, so only given attributes of the JSON should update the Layer sub-document. The following code works, but I have to specify each attribute that can be changed. Is there a better way to do it?

var update = {};
if (req.body.name !== undefined)
    update['layers.$.name'] = req.body.name;
if (req.body.isDefault !== undefined)
    update['layers.$.isDefault'] = req.body.isDefault;
if (req.body.isPublic !== undefined)
    update['layers.$.isPublic'] = req.body.isPublic;

Map.model.findOneAndUpdate({_id: req.params.mapId, 'layers._id': req.params.layerId}, update, callback);

node.js
mongodb
express
mongoose

Answer 1

You can make a function like this:

function updateParams(reqParams,additionalInfo)
{
    var update = {};
    for(var paramName in reqParams)
    {
        if(reqParams.hasOwnProperty(paramName))
        {
            if(reqParams[paramName]!==undefined)
            {
                update[additionalInfo+paramName] = reqParams[paramName];
            }
        }
    }
    return update;

}

updateParams(req.body,'layers.$.');

Answer 2

I have you considered JsonPatch this project converts json patch to mongo atomic updates: jsonpatch-to-mongodb