add proof leaf method

.gitignore

@@ -4,3 +4,4 @@ lib
 yarn-error.log
 .idea
 .nyc_output
+.run

src/FixedMerkleTree.ts

@@ -1,7 +1,6 @@
 import {
   Element,
   HashFunction,
-  Index,
   MerkleTreeOptions,
   ProofPath,
   SerializedTreeState,
@@ -147,7 +146,7 @@ export default class MerkleTree {
    * @param {number} index Leaf index to generate path for
    * @returns {{pathElements: Object[], pathIndex: number[]}} An object containing adjacent elements and left-right index
    */
-  path(index: Index): ProofPath {
+  path(index: number): ProofPath {
     if (isNaN(Number(index)) || index < 0 || index >= this._layers[0].length) {
       throw new Error('Index out of bounds: ' + index)
     }
@@ -194,8 +193,7 @@ export default class MerkleTree {
   }
 
   getTreeEdge(edgeElement: Element): TreeEdge {
-    const leaves = this._layers[0]
-    const edgeIndex = leaves.indexOf(edgeElement)
+    const edgeIndex = this.indexOf(edgeElement)
     if (edgeIndex <= -1) {
       throw new Error('Element not found')
     }

src/PartialMerkleTree.ts

@@ -167,7 +167,7 @@ export class PartialMerkleTree {
     }
   }
 
-  path(index: Element): ProofPath {
+  path(index: number): ProofPath {
     if (isNaN(Number(index)) || index < 0 || index >= this._layers[0].length) {
       throw new Error('Index out of bounds: ' + index)
     }
@@ -205,6 +205,11 @@ export class PartialMerkleTree {
     }
   }
 
+  proof(element: Element): ProofPath {
+    const index = this.indexOf(element)
+    return this.path(index)
+  }
+
   serialize(): SerializedPartialTreeState {
     const leaves = this.layers[0].slice(this._edgeLeaf.index)
     return {

src/index.ts

@@ -38,6 +38,5 @@ export type TreeEdge = {
   edgePath: ProofPath;
   edgeIndex: number
 }
-export type Index = Element
 export type LeafWithIndex = { index: number, data: Element }
 

test/partialMerkleTree.spec.ts

@@ -163,6 +163,13 @@ describe('PartialMerkleTree', () => {
     })
   })
 
+  describe('#proof', () => {
+    it('should return proof for known leaf', () => {
+      const { partialTree } = getTestTrees(10, [1, 2, 3, 4, 5], 3)
+      assert.deepEqual(partialTree.proof(4), partialTree.path(3))
+    })
+  })
+
   describe('#getters', () => {
     it('should return capacity', () => {
       const levels = 10
@@ -207,6 +214,7 @@ describe('PartialMerkleTree', () => {
       const { partialTree } = getTestTrees(10, [1, 2, 3, 4, 5, 6, 7, 8, 9], 5)
       should().throw((() => partialTree.path(-1)), 'Index out of bounds: -1')
       should().throw((() => partialTree.path(10)), 'Index out of bounds: 10')
+      // @ts-ignore
       should().throw((() => partialTree.path('qwe')), 'Index out of bounds: qwe')
     })