MissingTranslationHandler API

Use the MissingTranslationHandler to customize what is happening in case a translation is missing.

This is influenced by the fallbackLang configuration. If a fallback language is configured, ngx-translate will first try to find the translation ID in the fallback language. If this is not available, the MissingTranslationHandler is called. If no fallback language is set, the handler is called immediately.

API

export interface MissingTranslationHandlerParams {
  key: string;
  translateService: TranslateService;
  interpolateParams?: Object;
}

export abstract class MissingTranslationHandler {
  abstract handle(params: MissingTranslationHandlerParams): any;
}

API Description

The handle() function is called for each missing translation. It receives a MissingTranslationHandlerParams object with the following properties:

• key - the ID of the translation that was not found
• translateService - the current TranslateService object
• interpolateParams - an object containing all parameters passed for the translation string

The default MissingTranslationHandler returns the ID of the translated message.

Depending on the result of the function:

• If it returns a value, then this value is used.
• If it returns an observable, the value returned by this observable will be used (except if the translation was done using instant()).
• If the result is undefined the key will be used as a value

How to Build a Custom Handler

For detailed examples and step-by-step instructions on building and registering custom missing translation handlers, see How to handle missing translations.