Pass parameter/argument to axios interceptor

Working solution

It's actually fairly simple to add parameters to the query with Axios interceptors when you send data.

axios.interceptors.request.use((config) => {
  config.params = {my_variable: 'value'}
  return config
})

The method suggested by @Laurent will cause axios to wipe out all your other parameters and replace it with my_variable, which is may not exactly what you want.

The proper way of adding default parameters instead of replacing it is like this:

axios.defaults.params = {};
axios.interceptors.request.use(function (config) {
    config.params['blah-defaut-param'] = 'blah-blah-default-value';
    return config;
}, function (error) {
    return Promise.reject(error);
});

This works with axios 0.18.1. It does not work with axios 0.19 due to a regression bug..., I believe it will be fixed soon.

Merge params

axios.interceptors.request.use((config) => {
  config.params = {...config.params, my_variable: 'value'}
  return config
})

axios allows to pass some additional request parameters:

axios.post('/api', `some body`,
    {headers: {'Content-Type': ' text/html;charset=UTF-8'},
    param: true});

and interceptor:

 this.axios.interceptors.request.use(req => {   
    console.log(`${req.method}: ${req.param}`); //output: `/api: true`
    return req;
    });

I have tested it on version: 0.21.1