How can I merge a project email template in script? Nothing seems to work.

Sample 1 (throws invalid record type job)

render.mergeEmail({
entity : {
     type: 'job',
     id: newRecord.id
    },
templateId:2
});

Sample 2 (throws invalid record type project)

render.mergeEmail({
entity: {
     type: 'project',
     id: newRecord.id
    },
templateId:2
});

Sample 3 (no error but doesn't resolve project fields)

render.mergeEmail({
entity :{
     type: 'customer',
     id: newRecord.id
    },
templateId:2
});