Sample SF LWC toaster utility

MyComponent.js

// SAMPLE USAGE
import * as toaster from 'c/toaster';

export default class MyComponent extends LightningElement {}

  connectedCallback() {
    toaster.init(this);
  }
  
  save() {
    toaster.success('Success!', 'Good job!');
  }
}

Toaster.js

// TOASTER UTIL
import { ShowToastEvent } from 'lightning/platformShowToastEvent';

let component = null;

const init = (cmp) => {
  component = cmp;
};

const toast = (title, message, variant, mode) => {
  if (!component) {
    throw new Error('Component is null. Call init with `this`.');
  }

  const event = new ShowToastEvent({
    title,
    message,
    variant,
    mode
  });

  component.dispatchEvent(event);
};

const error = (title, message) => {
  toast(title, message, 'error', 'sticky');
};

const warning = (title, message) => {
  toast(title, message, 'warning', 'pester');
};

const success = (title, message) => {
  toast(title, message, 'success', 'dismissible');
};

const info = (title, message) => {
  toast(title, message, 'info', 'dismissible');
};

export { init, error, warning, success, info };

The usage required a tiny bit of boilerplate in the connectedCallback, but I think it's better than having to deal with the ShowToastEvent import and verbose method signature(s) in order to get to the final dispatchEvent call.