Memory leak with responseType: 'text' and 'Content-Type': 'text/html'

Describe the bug Hello, I don’t know if it’s a V8 issue or Axios issue. When I send a get request to get HTML content on a page, a memory leak appear : the html is never stored in garbage collector…

To Reproduce I create a simple server.js with express and axios client to test outside of my project:

const express = require('express');
const axios = require('axios');

const server = express();
const axiosClient = axios.create();

server.get('/axios-test-html', async (req, res) => {
  try {
    const data = await axiosClient.get('https://github.com/winstonjs/winston-daily-rotate-file/pull/185', {
      responseType: 'text',
    });
    const htmlResponse = data.data;
    return res.send({
      sourceCode: htmlResponse,
    });
  } catch (error) {
    console.log(error);
    return res.status(500).send(error);
  }
})

server.listen('4242', () => {
  console.log('server listen at 4242');
});

process.on('SIGINT', () => {
  console.log('server signint');
  process.exit(0);
});

I’ve running my server.js with node --inspect and create heap snapshots at the beginning and after 3/4 calls.

Expected behavior Normally a memory leak does not appear with json content, but with html yes.

Environment:

• Axios Version [e.g. 0.18.0]
• OS: 10.14
• Browser: Chrome
• Browser: Version 71.0.3578.98
• Node.JS : 10.14.1

[Tarabyte]

@mehdibeldji Before PR is merged (if it ever would be 🤣 ) you could pass a custom response transformer that does nothing. This should eliminate the leak.

const axiosClient = axios.create({
  transformResponse: function(data, headers) {
    // use JSON.parse only if headers['content-type'].includes('application/json')
    // or always return data if you don't plan to use this client to fetch json
    return data 
  }
});

[Tarabyte]

This seems to be V8 issue caused by JSON.parse. I’ve filed a bugreport.

The simplest way to reproduce the issue w/o axios

setInterval(() => {
  const hugeNonJSONString = '*'.repeat(10 ** 6)

  try {
    JSON.parse(hugeNonJSONString)
  } catch (ignored) {
    // swallow
  }
}, 1000)