ResourceStore options doesn't update on instance clone

[GheorgheP]

🐛 Bug Report

When clone the instance using i18n.cloneInstance, the ResourceStore is not cloned with new options.
Specifically in my case the keySeparator is used from original instance.

To Reproduce

const instance = i18n.cloneInstance({
  keySeparator: '[[my-new-separator]]'
})

Then try to translate a text with the new instance:

instance.t('my-key[[my-new-separator]]value');

When trying to translate with original instance key separator, it does translate.

Cause

I investigated the problem and it is cause by the fact that we create the ResourceStore at the init, but only when new instance is created, not cloned. So it is initialised only with initial options:

i18next/src/i18next.js

Lines 83 to 102 in 18ce83f

	if (!this.options.isClone) {
	if (this.modules.logger) {
	baseLogger.init(createClassOnDemand(this.modules.logger), this.options);
	} else {
	baseLogger.init(null, this.options);
	}
	let formatter;
	if (this.modules.formatter) {
	formatter = this.modules.formatter;
	} else if (typeof Intl !== 'undefined') {
	formatter = Formatter;
	}
	const lu = new LanguageUtils(this.options);
	this.store = new ResourceStore(this.options.resources, this.options);
	const s = this.services;
	s.logger = baseLogger;
	s.resourceStore = this.store;

[jamuhl]

i18n.cloneInstance reuses same resources -> so why should the separators be different using same translations?!?

[adrai]

Better use different instances => https://www.i18next.com/overview/api#createinstance

[GheorgheP]

i18n.cloneInstance reuses same resources -> so why should the separators be different using same translations?!?

The idea is simple. I have a react app, that uses a UI library (also made by me). So I pass to that ui library the i18n instance for it's internal translations. But that UI library queries that strings different from my main app (because it was made independent from my main app).
In the end I have the necessary translations with the proper structure, but the separator strings or context/plural separators are different.

Maybe we can create something like ResourceStore.cloneInstance similar to i18n.cloneInstance, so you can change the options that doesn't affects the resources. I do understand that creating a new ResourceStore may no be a good idea, or a bad idea at all, but we can use the same clone strategy.

[GheorgheP]

Better use different instances => https://www.i18next.com/overview/api#createinstance

In my case this is not a good idea as I use remote translations and creating a new instance would mean to lod twice the resources.

[adrai]

v23.1.0 introduces a new cloneInstance option:

const instance = i18n.cloneInstance({
  forkResourceStore: true,
  keySeparator: '[[my-new-separator]]'
})