Internal Should not be instantiated by the user.
Protected Internal _permitsPoor man's sealed class. See BaseClientEvent._permits for more info.
Internal _propagationReadonly elapsedThe elapsed time since the command was started, in milliseconds.
Optional Readonly extraAny extra information that may be useful for logging/debugging purposes.
Some commands may set this; others may not. Guaranteed to always have at least one key if not undefined.
Readonly invokingThe method which invoked the request
Readonly isWhether the command is long-running or not, i.e. requires polling.
Readonly nameThe name of the event (e.g., 'CommandStarted', 'CommandFailed').
Readonly pollThe number of times polled so far
Readonly pollThe polling interval, in milliseconds.
Optional Readonly requestThe request body, if any.
Readonly requestA unique identifier for the request that triggered this event.
It helps correlate multiple events occurring within the same request lifecycle.
High-level operations, such as collection.insertMany(...), may generate multiple requests internally. Each of these requests will have its own unique requestId.
As an example, a CommandStarted event may be emitted when a command is started, and a CommandSucceeded event may be emitted when the command has succeeded. Both of these events will have the same requestId.
If logged to a file (e.g. winston with a file transport and json format), you could then filter all events with the same requestId to see the entire lifecycle of a single command.
// Set up event listeners on the collection
collection.on('commandStarted', (e) => {
console.log(`Command started with requestId: ${e.requestId}`);
});
collection.on('commandSucceeded', (e) => {
console.log(`Command succeeded with requestId: ${e.requestId}`);
});
// Logs:
// - Command started with requestId: dac0d3ba-79e8-4886-87b9-20237c507eba
// - Command succeeded with requestId: dac0d3ba-79e8-4886-87b9-20237c507eba
await collection.insertOne({ name: 'Alice' });
// Logs:
// - Command started with requestId: 1fe46a92-8187-4eaa-a3c2-80a964b68eba
// - Command succeeded with requestId: 1fe46a92-8187-4eaa-a3c2-80a964b68eba
await collection.insertOne({ name: 'Bob' });
Readonly requestThe HTTP method for the request.
Optional Readonly requestThe query parameters, if any.
Readonly timestampThe timestamp of when the event was created.
Readonly urlThe path for the request, not including the Base URL.
Protected _modifyFormats the event into a human-readable string, as it would be logged to stdout/stderr (if enabled).
See EventFormatter & BaseClientEvent.setDefaultFormatter for more information about custom formatting.
Optional custom formatter function.
The formatted event string.
Converts the event to a verbose JSON format, as it would be logged to stdout:verbose/stderr:verbose (if enabled).
Useful for debugging. The output is pretty-printed JSON with newlines, so perhaps not ideal for structured logging though.
A JSON string with full event details.
Stops the event from bubbling up to the parent listener (e.g. Collection → Db → DataAPIClient) and prevents any further listeners from being called.
db.on('commandStarted', (e) => {
console.log('Command started (db listener)');
});
collection.on('commandStarted', (e) => {
console.log('Command started (collection listener #1)');
e.stopImmediatePropagation();
});
collection.on('commandStarted', (e) => {
console.log('Command started (collection listener #2)');
});
// Logs:
// - Command started (collection listener #1)
collection.insertOne({ name: 'Alice' });
stopPropagation
Stops the event from bubbling up to the parent listener (e.g. Collection → Db → DataAPIClient).
client.on('commandStarted', (e) => {
console.log('Command started (client listener)');
});
db.on('commandStarted', (e) => {
console.log('Command started (db listener)');
e.stopPropagation();
});
collection.on('commandStarted', (e) => {
console.log('Command started (collection listener)');
});
// Logs:
// - Command started (collection listener)
// - Command started (db) listener
collection.insertOne({ name: 'Alice' });
stopImmediatePropagation
Static setSets the default formatter for all events.
Useful especially if you want to change the format of events as they're logged to stdout/stderr (see LoggingOutputs).
See EventFormatter for much more info.
This method sets a static property on the class, so it will affect all instances of BaseClientEvent, regardless of the class. Be careful when using this method in a shared environment.
A function that transforms an event into a log string.
BaseClientEvent.setDefaultFormatter((event, msg) => `[${event.name}] ${msg}`);
Event emitted when a command is polling in a long-running operation (i.e. create database).
Emits every time the command polls.
See AdminCommandEvent for more information about all the common properties available on this event.