In Trans.js, set default value to undefined as last possible option

[dominicboutin]

Using Trans component, if node is left empty, default value is set to a empty string. I18next will use that default value instead of its fallback mechanism. By setting the default value to undefined will let i18next define what fallback to use.

[coveralls]

Coverage remained the same at 81.557% when pulling 1152ab9 on dominicboutin:restore-fallback-mechanism into 844e7dd on i18next:master.

[coveralls]

Coverage remained the same at 81.557% when pulling 1152ab9 on dominicboutin:restore-fallback-mechanism into 844e7dd on i18next:master.

[jamuhl]

isn't defaultValue not just used in case of the fallback not finding something: https://github.com/i18next/i18next/blob/master/src/Translator.js#L122

could you describe more / or make a sample what fallback mechanism you mean?

[dominicboutin]

Exactly, since defaultValue is set to a empty string and res is undefined,
https://github.com/i18next/i18next/blob/master/src/Translator.js#L126
usedkey isn't set to true
res isn't set to key

plus that skip the parseMissingKeyHandler function
https://github.com/i18next/i18next/blob/master/src/Translator.js#L177

[jamuhl]

cause empty string is considered valid value per default: https://github.com/i18next/i18next/blob/master/src/defaults.js#L31

potentially this could break existing projects. could we make it a pick from reactI18nextOptions.defaultTransDefaultValueFallback which defaults to empty string so it will be backwards compatible

[jamuhl]

beside how are you using the Trans component to not have a meaningful defaultValue...do you use it everywhere to just render plain strings not having a component interpolated? if so that could be done by just using the t function from the hoc, render prop

[dominicboutin]

We are using TypeScript, its easier to use Trans in our components than set the prop type to include t.
<Trans i18nKey="somekey" />

Setting returnEmptyString to false fixes our issues but I feel like the default Trans value should undefined.
Adding a reactI18nextOptions.defaultTransDefaultValueFallback could be a solution or wait for the next major version.

On our side the issue is fixed with that workaround, this PR can be closed.

[jamuhl]

will keep this open for now - will add the defaultTransDefaultValueFallback asap. So you got that option.

[jamuhl]

closing this for now...added an issue to keep that for future development: #577

sorry for not yet having time to do so...a PR would be welcome

[jamuhl]

published in react-i18next@9.0.0

allow defining transEmptyNodeValue in i18next.options.react to set a default fallback value