filters

This page describes filters in zalo-bot-js, the built-in filter set used with MessageHandler or any flow that needs to inspect an Update.

The SDK filters are composable functions that can be combined with and, or, and not.

Built-in filters

filters.TEXT
filters.COMMAND
filters.PHOTO
filters.STICKER
filters.ALL

Basic example

ts

app.addHandler(new MessageHandler(filters.TEXT, async (update) => {
  await update.message?.replyText("This is a text message.");
}));

Combining filters

ts

const textButNotCommand = filters.TEXT.and(filters.COMMAND.not());

ts

const media = filters.PHOTO.or(filters.STICKER);

Next

See MessageHandler to use filters in handlers.
See Application to understand where filters fit in the runtime flow.

Last updated: April 5, 2026