How do I call a getter from another getter in Vuex?

Pass getters as the second argument to access local and non-namespaced getters. For namespaced modules, you should use rootGetters (as the 4th argument, in order to access getters defined within another module):

export default foo = (state, getters, rootState, rootGetters) => {
    return getters.yourGetter === rootGetters['moduleName/getterName']
}

In VueJS 2.0, you must pass both state and getters.

Getters are passed to other getters as the 2nd Argument:

export default foo = (state, getters) => {
    return getters.yourGetter
}

Official documentation: https://vuex.vuejs.org/guide/getters.html#property-style-access