Callback with no parameter

String comparison function.

  if (a < b) return -1
  if (a > b) return 1
  return 0

Callback that returns an Array of documents

Callback that returns a single document

Generic async function

Generic document in NeDB. It consists of an Object with anything you want inside.

Internal _id of the document, which can be null or undefined at some points (when not inserted yet for example).

Nedb query.

Each key of a query references a field name, which can use the dot-notation to reference subfields inside nested documents, arrays, arrays of subdocuments and to match a specific element of an array.

Each value of a query can be one of the following:

• string: matches all documents which have this string as value for the referenced field name
• number: matches all documents which have this number as value for the referenced field name
• Regexp: matches all documents which have a value that matches the given Regexp for the referenced field name
• object: matches all documents which have this object as deep-value for the referenced field name
• Comparison operators: the syntax is { field: { $op: value } } where $op is any comparison operator:
  • $lt, $lte: less than, less than or equal
  • $gt, $gte: greater than, greater than or equal
  • $in: member of. value must be an array of values
  • $ne, $nin: not equal, not a member of
  • $stat: checks whether the document posses the property field. value should be true or false
  • $regex: checks whether a string is matched by the regular expression. Contrary to MongoDB, the use of $options with $regex is not supported, because it doesn't give you more power than regex flags. Basic queries are more readable so only use the $regex operator when you need to use another operator with it
  • $size: if the referenced filed is an Array, matches on the size of the array
  • $elemMatch: matches if at least one array element matches the sub-query entirely
• Logical operators: You can combine queries using logical operators:
  • For $or and $and, the syntax is { $op: [query1, query2, ...] }.
  • For $not, the syntax is { $not: query }
  • For $where, the syntax is:

  { $where: function () {
    // object is 'this'
    // return a boolean
  } }
  

Nedb projection.

You can give find and findOne an optional second argument, projections. The syntax is the same as MongoDB: { a: 1, b: 1 } to return only the a and b fields, { a: 0, b: 0 } to omit these two fields. You cannot use both modes at the time, except for _id which is by default always returned and which you can choose to omit. You can project on nested documents.

To reference subfields, you can use the dot-notation.

The beforeDeserializationand afterDeserialization callbacks should