Nesting
Nesting allows you to reference other keys in a translation. Could be useful to build glossary terms.

Basic

keys
{
"nesting1": "1 $t(nesting2)",
"nesting2": "2 $t(nesting3)",
"nesting3": "3",
}
sample
i18next.t('nesting1'); // -> "1 2 3"
You can reference keys from other namespaces by prepending the namespace: "nesting1": "1 $t(common:nesting2)",

Passing options to nestings

You can pass entire data models in options.
keys
{
"girlsAndBoys": "They have $t(girls, {\"count\": {{girls}} }) and $t(boys, {\"count\": {{boys}} })",
"boys": "{{count}} boy",
"boys_other": "{{count}} boys",
"girls": "{{count}} girl",
"girls_other": "{{count}} girls",
}
sample
i18next.t('girlsAndBoys', {girls: 3, boys: 2});
// -> "They have 3 girls and 2 boys"
Make sure the options string is valid JSON and can be parsed using JSON.parse
'sampleKey': 'test $t(nest2, { "changedVarName": "{{var}}" })'

Passing nesting to interpolated

keys
{
"key1": "hello world",
"key2": "say: {{val}}"
}
sample
i18next.t('key2', {val: '$t(key1)'});
// -> "say: hello world"
If you're using >= v21.0.0 you need to set skipOnVariables to false:
interpolation: {
skipOnVariables: false
}

Additional options

Prefix/Suffix for nesting and other options can be overridden in init interpolation options or by passing additional options to t function:
sample
i18next.init({
interpolation: { ... }
});
i18next.t('key', {
interpolation: { ... }
});
option
default
description
nestingPrefixEscaped
undefined
escaped prefix for nesting (regexSafe)
nestingSuffixEscaped
undefined
escaped suffix for nesting (regexSafe)
While there are a lot of options going with the defaults should get you covered.