send stdin or arguments to slack like chat via webhook

chat.js

#!/usr/bin/env node

/* references
- [How to get node.js HTTP request promise without a single dependency](https://www.tomas-dvorak.cz/posts/nodejs-request-without-dependencies/)
- [Process | Node.js v8.5.0 Documentation](https://nodejs.org/api/process.html#process_process_stdin)
  - stdin
- [HTTP | Node.js v8.5.0 Documentation](https://nodejs.org/docs/latest/api/http.html#http_http_request_options_callback)
  - request
- [URL | Node.js v8.5.0 Documentation](https://nodejs.org/docs/latest/api/url.html)
  - parse url
*/

const hook_url='https://webhook/url';
const channel='channel-name';
const icon=':deciduous_tree:';

const getStdin = function(){
  return new Promise((resolve, reject) => {
    process.stdin.setEncoding('utf8');

    var input = [];
    process.stdin.on('readable', () => {
      const chunk = process.stdin.read();
      if (chunk !== null) {
        input.push(chunk);
      }
    });

    process.stdin.on('end', () => {
      process.stdout.write(`> sending data:\n${input.join('')}`);
      resolve(input.join(''));
    });
  });
};

const postContent = function(url, data){
  return new Promise((resolve, reject) => {
    const postData = require('querystring').stringify(data);
    const urllib = require('url');
    const parsedUrl = urllib.parse(url);
    const options = {
      hostname: parsedUrl.host,
      port: url.startsWith('https') ? 443 : 80,
      path: parsedUrl.path,
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': Buffer.byteLength(postData)
      }
    };

    const lib = url.startsWith('https') ? require('https') : require('http');
    const req = lib.request(options, (res) => {
      // handle http errors
      if (res.statusCode < 200 || res.statusCode > 299) {
        reject(new Error('Failed to load page, status code: ' + res.statusCode));
      }


      // console.log(`STATUS: ${res.statusCode}`);
      // console.log(`HEADERS: ${JSON.stringify(res.headers)}`);
      res.setEncoding('utf8');

      const body = [];
      res.on('data', (chunk) => {
        // console.log(`BODY: ${chunk}`);
        body.push(chunk);
      });
      res.on('end', () => {
        // console.log('No more data in response.');
        resolve(body.join(''));
      });
    });

    req.on('error', (e) => {
      console.error(`problem with request: ${e.message}`);
      reject(e);
    });

    // write data to request body
    req.write(postData);
    req.end();
  });
};

getStdin().then(function(input){
  const mes = input;
  const data = {
    payload: JSON.stringify({
      icon_emoji: icon,
      text: '```' + mes + '```',
      channel: channel
    })
  };
  return postContent(hook_url, data);
})
.then(function(out){
  console.log('> done');
})
.catch(function(e){
  console.log('error', e);
});

chat.sh

#!/bin/bash

HOOK_URL='https://webhook/url'
CHANNEL='channel-name'
ICON=':cat:'

post() {
    local mes=$(cat - |perl -pe 's/\n/\\n/g'|perl -pe 's/"/\\"/g'|perl -pe "s/'/'\\\\''/g")
    curl -X POST --data-urlencode 'payload={"icon_emoji":"'$ICON'","text":"```'$mes'```","channel":"'$CHANNEL'"}' $HOOK_URL
}

if [ -p /dev/stdin ]; then
    cat -
else
    echo $@
fi | post