onText

This page describes the onText() function in zalo-bot-js, used to register a callback based on a regular expression applied to message.text.

This is the right choice when you want to match commands, keywords, or structured text patterns.

Function signature

onText(
  pattern: RegExp,
  callback: (message: Message, match: RegExpExecArray) => Promise<void> | void,
): this

Callback shape

The callback receives:

• message: Message
• match: RegExpExecArray

Example

bot.onText(/.*/, async (message, match) => {
  console.log("[onText]", {
    chatId: message.chat.id,
    match: match[0],
  });
});

Example with a command

bot.onText(/\/start(?:\s+(.+))?/, async (message, match) => {
  const payload = match[1]?.trim() ?? "there";
  await bot.sendMessage(message.chat.id, `Hello ${payload}!`);
});

Difference between on("text") and onText()

• on("text") runs for every text message
• onText() runs only when the regex matches

Next

• See on for event-based listeners.
• See sendMessage to respond from the callback.

Last updated: April 5, 2026