https://github.com/smartprix/tail
Watch and tail a file in nodejs (similar to tail -f -n)
https://github.com/smartprix/tail
logs node stream tail
Last synced: about 2 months ago
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Watch and tail a file in nodejs (similar to tail -f -n)
- Host: GitHub
- URL: https://github.com/smartprix/tail
- Owner: smartprix
- Created: 2018-10-07T08:47:46.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2018-10-07T09:28:29.000Z (over 6 years ago)
- Last Synced: 2025-03-25T05:03:25.555Z (2 months ago)
- Topics: logs, node, stream, tail
- Language: JavaScript
- Homepage:
- Size: 4.88 KB
- Stars: 3
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# @smpx/tail
Watch and tail a file in nodejs `tail -f -n` 🎉 **No Dependencies**
### Install
```sh
npm install @smpx/tail
```
Or with yarn:
```sh
yarn add @smpx/tail
```
### Use
```js
const tail = require('@smpx/tail');
const stream = tail('/var/log/syslog', {
numLines: 20,
watch: true,
});
stream.on('line', (line) => {
console.log(line);
});
stream.on('error', (err) => {
console.error(err);
});
```
If you want to stop watching:
```js
stream.close();
```
### API
#### tail(filename, options)
* `filename`: Path of the file to tail
* `options`:
* `bufferSize`: Use this bufferSize when reading from the file (default `2048`)
* `encoding`: Encoding of the file (default `utf8`)
* `numLines`: Number of lines to read initially (default `10`) (similar to `tail -n`)
* `watch`: Whether to watch the file for changes (default `false`) (similar to `tail -f`)
* Setting this to true will keep the process alive until you call `close`
* `filter`: An optional function to emit only those lines which pass the criteria
```js
const stream = tail('/var/log/syslog', {
numLines: 20,
watch: true,
filter: (line) => {
if (!line) return false;
return JSON.parse(line).level === 'error';
}
});
```
**Returns**:
An eventemitter, with two events, `line` and `error` and a function `close`.
* `on('line', (line) => {})`: emitted whenever we read a new line from the file
* `on('error', (err) => {})`: emitted whenever there's an error
* `close`: a method to close and unwatch the file
### LICENSE
MIT