Provable
type Provable<T, TValue>: {
check: (value: T) => void;
fromFields: (fields: Field[], aux: any[]) => T;
fromValue: (x: TValue | T) => T;
toAuxiliary: (value?: T) => any[];
toFields: (value: T) => Field[];
toValue: (x: T) => TValue;
sizeInFields: number;
};
Provable<T> is the general interface for provable types in o1js.
Provable<T> describes how a type T is made up of Field elements and "auxiliary" (non-provable) data.
Provable<T> is the required input type in several methods in o1js.
One convenient way to create a Provable<T> is using Struct.
All built-in provable types in o1js (Field, Bool, etc.) are instances of Provable<T> as well.
Note: These methods are meant to be used by the library internally and are not directly when writing provable code.
Type parameters
• T
• TValue = any
Type declaration
check()
check: (value: T) => void;
Add assertions to the proof to check if value is a valid member of type T.
This function does not return anything, instead it creates any number of assertions to prove that value is a valid member of the type T.
For instance, calling check function on the type Bool asserts that the value of the element is either 1 or 0.
Parameters
• value: T
the element of type T to put assertions on.
Returns
void
fromFields()
fromFields: (fields: Field[], aux: any[]) => T;
A function that returns an element of type T from the given provable and "auxiliary" data.
This function is the reverse operation of calling toFields and toAuxilary methods on an element of type T.
Parameters
• fields: Field[]
an array of Field elements describing the provable data of the new T element.
• aux: any[]
an array of any type describing the "auxiliary" data of the new T element, optional.
Returns
T
fromValue()
fromValue: (x: TValue | T) => T;
Convert provable type from a normal JS type.
Parameters
• x: TValue | T
Returns
T
toAuxiliary()
toAuxiliary: (value?: T) => any[];
A function that takes value (optional), an element of type T, as argument and
returns an array of any type that make up the "auxiliary" (non-provable) data of value.
Parameters
• value?: T
the element of type T to generate the auxiliary data array from, optional.
If not provided, a default value for auxiliary data is returned.
Returns
any[]
toFields()
toFields: (value: T) => Field[];
A function that takes value, an element of type T, as argument and returns
an array of Field elements that make up the provable data of value.
Parameters
• value: T
the element of type T to generate the Field array from.
Returns
Field[]
toValue()
toValue: (x: T) => TValue;
Convert provable type to a normal JS type.
Parameters
• x: T
Returns
TValue
sizeInFields()
Return the size of the T type in terms of Field type, as Field is the primitive type.
Returns
number
A number representing the size of the T type in terms of Field type.