# Defining fields

To define the fields of a list add their names to the fields object and set their initial state.

E.g., to add the fields amount and recipient to a list of invoices, use the following code:

const fields = {
  amount: { initialState: 0 },
  recipient: { initialState: '' }
};

# Speeding up reading lists

For fields that are queried often it may make sense to index them. To do so, add the fastLookup property to the field's definition and set it to true. Avoid applying this to every field, as this may actually degrade performance.

E.g., to add an index to the recipient field of the list of invoices, use the following code:

const fields = {
  amount: { initialState: 0 },
  recipient: { initialState: '', fastLookup: true }
};

# Marking fields as unique

Optionally, you may mark fields to be unique. For that, add the isUnique property and set it to true.

E.g., to mark the recipient field of the list of invoices as unique, use the following code:

const fields = {
  amount: { initialState: 0 },
  recipient: { initialState: '', fastLookup: true, isUnique: true }
};