Essentials

Accessing keys

resources with 2 keys:

{
    "key": "value of key",
    "look": {
        "deep": "value of look deep"
    }
}

sample

JavaScript

i18next.t('key');
// -> "value of key"

i18next.t('look.deep');
// -> "value of look deep"

TypeScript

Passing a default value

You can pass in a default value for cases the key could not be found in translations like:

JavaScript

i18next.t('key', 'default value to show');

TypeScript

In case you're using the saveMissing functionality, it will also pass the defaultValue to your chosen backend, like shown in this React.js example.

Accessing keys in different namespaces

Namespaces are a feature in i18next internationalization framework which allows you to separate translations that get loaded into multiple files.

init

i18next.init({
  ns: ['common', 'moduleA'],
  defaultNS: 'moduleA'
});

moduleA.json

{
    "name": "Module A"
}

common.json

{
    "button": {
        "save": "save"
    }
}

sample

JavaScript

i18next.t('name');
// -> "Module A"

// from different namespace (not recommended with namespace prefix when used in combination with natural language keys)
i18next.t('common:button.save') // -> "save"
// better use the ns option:
i18next.t('button.save', { ns: 'common' }) // -> "save"

TypeScript

Multiple fallback keys

Calling the t function with an array of keys enables you to translate dynamic keys providing a non specific fallback value.

As a sample think of an error code you get and you like to show a specific warning in some cases:

keys

{
  "error": {
    "unspecific": "Something went wrong.",
    "404": "The page was not found."
  }
}

sample

JavaScript

// const error = '404';
i18next.t([`error.${error}`, 'error.unspecific']); 
// -> "The page was not found"

// const error = '502';
i18next.t([`error.${error}`, 'error.unspecific']); 
// -> "Something went wrong"

TypeScript

Overview options

i18next.t(key, options)

option	description
defaultValue	defaultValue to return if a translation was not found, you also can define defaults for plurals by adding defaultValue_other -> _suffix depends on same pluralrules.
count	count value used for plurals
context	used for contexts (eg. male / female)
replace	object with vars for interpolation - or put them directly in options
lng	override language to use
lngs	override languages to use
fallbackLng	override language to lookup key if not found see fallbacks for details, passing false will not do a fallback to any language
ns	override namespaces (string or array)
keySeparator	override char to separate keys
nsSeparator	override char to split namespace from key
returnObjects	accessing an object not a translation string (can be set globally too)
returnDetails	returns an object that includes information about the used language, namespace, key and value
joinArrays	char, eg. '\n' that arrays will be joined by (can be set globally too)
postProcess	string or array of postProcessors to apply see interval plurals as a sample
interpolation	override interpolation options
skipInterpolation	skip interpolation and nesting for this call to t function
ignoreJSONStructure	if a key is not found as nested key, it will try to lookup as flat key