Class: IncrementalMerkleTree

The modified IncrementalMerkleTree which is used in Unirep protocol to generate global state tree. It inherited from IncrementalMerkleTree from @zk-kit/incremental-merkle-tree

Example

import { IncrementalMerkleTree } from '@unirep/utils'

const tree = new IncrementalMerkleTree(32)

Hierarchy

• default

  ↳ IncrementalMerkleTree

Constructors

constructor

• new IncrementalMerkleTree(depth, zeroValue?, arity?)

Initializes the tree with the hash function, the depth, the zero value to use for zeroes and the arity (i.e. the number of children for each node). Fixed hash function: poseidon

Parameters

Name	Type	Default value	Description
depth	number	undefined	Tree depth.
zeroValue	any	0	Zero values for zeroes (default: 0).
arity	number	2	The number of children for each node (default: 2).

Overrides

zkIncrementalMerkleTree.constructor

Defined in

packages/utils/src/IncrementalMerkleTree.ts:25

Properties

maxDepth

▪ Static Readonly maxDepth: 32

Inherited from

zkIncrementalMerkleTree.maxDepth

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:10

Accessors

arity

• get arity(): number

Returns the number of children for each node.

Returns

number

Number of children per node.

Inherited from

zkIncrementalMerkleTree.arity

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:50

---

depth

• get depth(): number

Returns the depth of the tree.

Returns

number

Tree depth.

Inherited from

zkIncrementalMerkleTree.depth

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:35

---

leaves

• get leaves(): any[]

Returns the leaves of the tree.

Returns

any[]

List of leaves.

Inherited from

zkIncrementalMerkleTree.leaves

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:40

---

root

• get root(): any

Returns the root hash of the tree.

Returns

any

Root hash.

Inherited from

zkIncrementalMerkleTree.root

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:30

---

zeroes

• get zeroes(): any[]

Returns the zeroes nodes of the tree.

Returns

any[]

List of zeroes.

Inherited from

zkIncrementalMerkleTree.zeroes

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:45

Methods

createProof

▸ createProof(index): MerkleProof

Creates a proof of membership.

Parameters

Name	Type	Description
index	number	Index of the proof's leaf.

Returns

MerkleProof

Proof object.

Inherited from

zkIncrementalMerkleTree.createProof

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:79

---

delete

▸ delete(index): void

Deletes a leaf from the tree. It does not remove the leaf from the data structure. It set the leaf to be deleted to a zero value.

Parameters

Name	Type	Description
index	number	Index of the leaf to be deleted.

Returns

void

Inherited from

zkIncrementalMerkleTree.delete

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:67

---

indexOf

▸ indexOf(leaf): number

Returns the index of a leaf. If the leaf does not exist it returns -1.

Parameters

Name	Type	Description
leaf	any	Tree leaf.

Returns

number

Index of the leaf.

Inherited from

zkIncrementalMerkleTree.indexOf

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:56

---

insert

▸ insert(leaf): void

Inserts a new leaf in the tree.

Parameters

Name	Type	Description
leaf	any	New leaf.

Returns

void

Inherited from

zkIncrementalMerkleTree.insert

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:61

---

update

▸ update(index, newLeaf): void

Updates a leaf in the tree.

Parameters

Name	Type	Description
index	number	Index of the leaf to be updated.
newLeaf	any	New leaf value.

Returns

void

Inherited from

zkIncrementalMerkleTree.update

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:73

---

verifyProof

▸ verifyProof(proof): boolean

Verifies a proof and return true or false.

Parameters

Name	Type	Description
proof	MerkleProof	Proof to be verified.

Returns

boolean

True or false.

Inherited from

zkIncrementalMerkleTree.verifyProof

Defined in

node_modules/@zk-kit/incremental-merkle-tree/dist/types/incremental-merkle-tree.d.ts:85