# and · FT4 TypeScript client · Chromia Docs (concept)

> and< T extends string>(...rules: SimpleRule < T >[]): ComplexRule < T > Creates a combination of rules that will be evaluated using the equivalent of a boo

Source: https://docs.chromia.com/pages/ft4-ts-client/functions/accounts.and/

Function

# and

* ```signature
  and<T extends string>(...rules: SimpleRule<T>[]): ComplexRule<T>
  ```

  Creates a combination of rules that will be evaluated using the equivalent of a boolean 'and' operator.
  I.e., for the expression returned by this function to be true, all of the provided rules must evaluate
  to true as well, the rules will be evaluated in the same order as they are provided and will short circuit
  if any rule evaluates to false.

  The object that is returned from this function can be used when creating an auth descriptor.

  Example:

  Plain text

  ```
   and(
     greaterThan(blockHeight(50)),
     lessThan(blockHeight(10)),
   )
  ```

  #### Type Parameters

  + T extends string

  #### Parameters

  + ...rules: [SimpleRule](https://docs.chromia.com/pages/ft4-ts-client/types/accounts.SimpleRule/)<[T](#andt)>[]

    the rules to combine

  #### Returns [ComplexRule](https://docs.chromia.com/pages/ft4-ts-client/types/accounts.ComplexRule/)<[T](#andt)>

  a set of rules which will be evaluated together using the 'and' operator

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-ts-client/functions/accounts.and.html)Generated API reference, mirrored from the live docs