MissingTranslationHandler API

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

This is also influenced by the configuration value useDefaultLang. If useDefaultLang=true, ngx-translate will first try to find the translation ID in the default language. If this is not available, the MissingTranslationHandler is called. If useDefaultLang=false, the handler is called immediately.

The default MissingTranslationHandler returns the ID of the translated message.

To implement your own handler, derive from MissingTranslationHandler and pass the handler during the initialization of the TranslateModule.

An example is available from here: How to handle missing translations.

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

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

The handle() function is called for each missing translation. It receives an object with the following values:

• 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

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