Override filtering behavior

This is the official documentation of the @forestadmin/agent Node.js agent.

You may want to read about the following topics before using those features:

Disabling operators

Disabling filtering can be made without any code in the field settings ↗.


Operation substitution can be used for two motives:

  • Performance: provide a more efficient way to perform a given filtering operation

  • Capabilities: enable filtering on a computed field or other non-filterable fields

collection.replaceFieldOperator('fullName', 'Equal', (value, context) => {
  const [firstName, ...lastNames] = value.split(' ');

  return {
    aggregator: 'And',
    conditions: [
      { field: 'firstName', operator: 'Equal', value: firstName },
      { field: 'lastName', operator: 'Equal', value: lastNames.join(' ') },
Column TypeOperator to support






IContains OR Contains OR Equal



You can use the replaceFieldOperator method to unlock the operators.


Filtering emulation allows making fields filterable automatically. It is a convenient way to get things working quickly for Collections that have a low number of records (in the thousands at most).

This emulation forces the Agent to retrieve all the Collection records and compute the field values for each one of them. As a consequence, filtering emulation performance cost is linear with the number of records in the Collection, so activate it sparingly and with great care.

// Add support for all operators

// Add support for a single operator
collection.emulateFieldOperator('fullName', 'Equal');

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