MerkleTree.js

MerkleTree.js

class MerkleTree {
    constructor(leaves, concat) {
        this.leaves = leaves;
        this.concat = concat;
    }
    getProof(index, leaves = this.leaves, proof = []) {
        if (leaves.length === 1) {
            return proof;
        }
        let newLayer = [];
        for (let i = 0; i < leaves.length; i += 2) {
            let left = leaves[i];
            let right = leaves[i + 1];
            if (right) {
                if(index === i) {
                    proof.push({
                        data: right,
                        left: false,
                    });
                }
                if(index === i + 1) {
                    proof.push({
                        data: left,
                        left: true,
                    });
                }
                newLayer.push(this.concat(left, right));
            }
            else {
                newLayer.push(left);
            }
        }
        return this.getProof(Math.floor(index/2), newLayer, proof);

    } 
    getRoot(leaves = this.leaves) {
        if (leaves.length === 1) {
            return leaves[0];
        }
        let newLayer = [];
        for (let i = 0; i < leaves.length; i += 2) {
            let left = leaves[i];
            let right = leaves[i + 1];
            if(right) {
                newLayer.push(this.concat(left, right));
            }
            else {
                newLayer.push(left);
            }
        }
        return this.getRoot(newLayer);
    }
}

module.exports = MerkleTree;