SailsJS, Waterline populate records with select - orm

Question

I have looked at a lot of old SO questions which have broken GitHub links and SailsJS Trello, however I am still unclear.
Is it possible, to populate a field (one-to-one relationship) in SailsJS and return only specific fields (either via select or omit).
await Document.find({id: id}).populate('createdBy', {select: ['name']})
I am getting
UsageError: Invalid populate(s).
Details:
Could not populate `createdBy` because of ambiguous usage. This is a singular ("model") association, which means it never refers to more than _one_ associated record. So passing in subcriteria (i.e. as the second argument to `.populate()`) is not supported for this association
, since it generally wouldn't make any sense. But that's the trouble-- it looks like some sort of a subcriteria (or something) _was_ provided!
(Note that subcriterias consisting ONLY of `omit` or `select` are a special case that _does_ make sense. This usage will be supported in a future version of Waterline.)
Here's what was passed in:
{ select: [ 'name' ] }
In models,
createdBy: {
model: 'user',
description: 'Who is this document assigned to'
},
I am using sails 1.1.0, waterline 0.13.5-0
Am I doing this right? Is there a way to do this?

Answer 1

I solved the problem and made a pull request. Since the pull request has not yet been accepted, be careful and use it on your ask.
Go to
node_modules/waterline/lib/waterline/utils/query/forge-stage-two-query.js
Go to this section
// If this is a singular ("model") association, then it should always have
// an empty dictionary on the RHS. (For this type of association, there is
// always either exactly one associated record, or none of them.)
if (populateAttrDef.model) {....}
Change it to:
if (populateAttrDef.model) {
// Tolerate a subcriteria of `{}`, interpreting it to mean that there is
// really no criteria at all, and that we should just use `true` (the
// default "enabled" value for singular "model" associations.)
if (_.isEqual(query.populates[populateAttrName], {})) {
query.populates[populateAttrName] = true;
}
// Otherwise, this simply must be `true`. Otherwise it's invalid.
else {
if (query.populates[populateAttrName] !== true && (_.isUndefined(query.populates[populateAttrName].select) && _.isUndefined(query.populates[populateAttrName].omit))) {
throw buildUsageError(
'E_INVALID_POPULATES',
'Could not populate `'+populateAttrName+'` because of ambiguous usage. '+
'This is a singular ("model") association, which means it never refers to '+
'more than _one_ associated record. So passing in subcriteria (i.e. as '+
'the second argument to `.populate()`) is not supported for this association, '+
'since it generally wouldn\'t make any sense. But that\'s the trouble-- it '+
'looks like some sort of a subcriteria (or something) _was_ provided!\n'+
'(Note that subcriterias consisting ONLY of `omit` or `select` are a special '+
'case that _does_ make sense. This usage will be supported in a future version '+
'of Waterline.)\n'+
'\n'+
'Here\'s what was passed in:\n'+
util.inspect(query.populates[populateAttrName], {depth: 5}),
query.using
);
}//-•
else {
query.populates[populateAttrName] = {
select: query.populates[populateAttrName].select? query.populates[populateAttrName].select : undefined,
omit: query.populates[populateAttrName].omit? query.populates[populateAttrName].omit : undefined
};
}
}//>-•
}
This is the pull request to see exactly what you should change:
https://github.com/balderdashy/waterline/pull/1613

Answer 2

When u use One-to-one association u can't use subcriteria like error say.
So passing in subcriteria (i.e. as the second argument to `.populate()`) is not supported for this association
U can use customToJSON function on model createdBy to omit data.
customToJSON: function() {
return _.omit(this, ['createdAt', 'updatedAt', 'id'])
}