This gist is part of an article and may not covey the actual message on it's own. Link to article: https://medium.com/@ejjay/a-short-ajax-story-on-error-handlers-8baeeccbc062

a-short-ajax-error-story-4-of-4.ts

import axios, {AxiosError} from 'axios';
import {notifier} from './util';

interface ComposedError {
    readonly message: string;
    readonly error: AxiosError;
    handleGlobally(): void;
    getError(): AxiosError;
}

class ComposedAjaxError implements ComposedError {
    name: string = 'ComposedAjaxError';
    public readonly message: string;
    public readonly error: AxiosError;

    private _globallyHandled: boolean = false;

    constructor(error: AxiosError) {
        this.error = error;
        const statusCode = error.response ? error.response.status : null;

        switch (statusCode) {
            case 401:
                this.message = 'Please login to access this resource';
                break;
            case 404:
                this.message = 'The requested resource does not exist or has been deleted';
                break;
            default:
                this.message = 'Something went wrong and request was not completed';
        }
    }

    public getError(): AxiosError {
        return this.error;
    }

    public handleGlobally(): void {
        if (this._globallyHandled) return;
        this._globallyHandled = true;
        notifier.error(this.message);
    };
}

axios.interceptors.response.use(undefined, function (error: AxiosError) {
    const composedError = new ComposedAjaxError(error);
    return Promise.reject(composedError);
})

// 1. Fetch some missing information
axios.get('/api/articles/not-found').then(resp => {
    // So something with article information
}).catch((error: ComposedError) => {
    const statusCode = error.getError().response 
        ? error.getError().response.status 
        : null;
    // We will handle locally
    // When it's a 404 error, else handle globally
    if (statusCode === 404) {
        // Do some specific error handling logic for this request
        // For example: show the user a paywall to upgrade their subscription in order to view achieves
    } else {
        error.handleGlobally && error.handleGlobally();
    }
})

// 2. Fetch some missing information
axios.get('/api/users/not-found').then(resp => {
    // So something with user information
}).catch((error: ComposedError) => {
    // We want to handle globally
    error.handleGlobally && error.handleGlobally();
})