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# Unique Values
In general, Faker methods do not return unique values.
```ts
faker.seed(55);
faker.animal.type(); //'cat'
faker.animal.type(); //'bird'
faker.animal.type(); //'horse'
faker.animal.type(); //'horse'
```
Some methods and locales use much smaller data sets than others. For example, `faker.animal.type` has only 13 possible animals to choose from. In contrast, `faker.person.fullName()` pulls from a list of hundreds of first names, surnames, and prefixes/suffixes, so it can generate hundreds of thousands of unique names. Even then, the [birthday paradox](https://en.wikipedia.org/wiki/Birthday_Paradox) means that duplicate values will quickly be generated.
Sometimes, you want to generate unique values. For example, you may wish to have unique values in a database email column.
There are a few possible strategies for this:
1. Use `faker.helpers.uniqueArray()` if you want to generate all the values at one time. For example:
```ts
faker.helpers.uniqueArray(faker.internet.email, 1000); // will generate 1000 unique email addresses
```
2. If there are insufficient values for your needs, consider prefixing or suffixing values with your own sequential values, for example you could prefix `1.`, `2.` to each generated email in turn.
3. Build your own logic to keep track of a set of previously generated values and regenerate values as necessary if a duplicate is generated
4. Use a third party package to enforce uniqueness such as [enforce-unique](https://github.com/MansurAliKoroglu/enforce-unique)
Note you can supply a maximum time (in milliseconds) or maximum number of retries.
```js
import { EnforceUniqueError, UniqueEnforcer } from 'enforce-unique';
const uniqueEnforcerEmail = new UniqueEnforcer();
function createRandomUser() {
const firstName = faker.person.firstName();
const lastName = faker.person.lastName();
const email = uniqueEnforcerEmail.enforce(
() =>
faker.internet.email({
firstName,
lastName,
}),
{
maxTime: 50,
maxRetries: 50,
}
);
return {
firstName,
lastName,
email,
};
}
```
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