in src/core/plugins/err/error-transformers/transformers/not-of-type.js [17:29]
function makeNewMessage(types) {
return types.reduce((p, c, i, arr) => {
if(i === arr.length - 1 && arr.length > 1) {
return p + "or " + c
} else if(arr[i+1] && arr.length > 2) {
return p + c + ", "
} else if(arr[i+1]) {
return p + c + " "
} else {
return p + c
}
}, "should be a")
}