Add miksi js lib for build witness calculation

src/miksi.ts

@@ -0,0 +1,89 @@
+const fs = require("fs");
+const bigInt = require("big-integer");
+const { groth } = require('snarkjs');
+const { stringifyBigInts, unstringifyBigInts } = require('ffjavascript').utils;
+const WitnessCalculatorBuilder = require("circom_runtime").WitnessCalculatorBuilder;
+const circomlib = require("circomlib");
+const smt = require("circomlib").smt;
+const Web3 = require("web3");
+// const buildBn128 = require("wasmsnark").buildBn128;
+
+
+const nLevels = 5;
+const coinCode = "0"; // refearing to ETH
+const ethAmount = '1';
+const amount = Web3.utils.toWei(ethAmount, 'ether');
+
+// let bn128;
+// 
+// exports.init = async () => {
+//         bn128 = await buildBn128();
+// }
+
+exports.calcWitness = async (wasm, secret, nullifier, commitments) => {
+	const poseidon = circomlib.poseidon.createHash(6, 8, 57);
+	const commitment = poseidon([coinCode, amount, secret, nullifier]).toString();
+
+	let tree = await smt.newMemEmptyTrie();
+	await tree.insert(1, 0);
+
+	// old root
+	const rootOld = tree.root;
+	const resOld = await tree.find(commitment);
+	if (resOld.found) {
+		console.error("leaf expect to not exist but exists");
+	}
+	let siblingsOld = resOld.siblings;
+	while (siblingsOld.length < nLevels) {
+		siblingsOld.push("0");
+	};
+
+	await tree.insert(commitment, 0);
+
+	// new root
+	const rootNew = tree.root;
+	const resNew = await tree.find(commitment);
+	if (!resNew.found) {
+		console.error("leaf expect to exist but not exists");
+	}
+	let siblingsNew = resNew.siblings;
+	while (siblingsNew.length < nLevels) {
+		siblingsNew.push("0");
+	};
+
+	// calculate witness
+	const input = unstringifyBigInts({
+		"coinCode": coinCode,
+		"amount": amount,
+		"secret": secret,
+		"nullifier": nullifier,
+		"siblingsOld": siblingsOld,
+		"siblingsNew": siblingsNew,
+		"rootOld": rootOld,
+		"rootNew": rootNew,
+		"commitment": commitment
+	});
+	console.log("input", input);
+	// const options = {};
+	// const wc = await WitnessCalculatorBuilder(wasm, options);
+
+	const wc = await WitnessCalculatorBuilder(wasm);
+
+	const witness = await wc.calculateWitness(input, {sanityCheck: true});
+
+	const wBuff = Buffer.allocUnsafe(witness.length*32);
+
+	for (let i=0; i<witness.length; i++) {
+		for (let j=0; j<8; j++) {
+			const bi = witness[i];
+			const v = bigInt(bi).shiftRight(j*32).and(0xFFFFFFFF).toJSNumber();
+			wBuff.writeUInt32LE(v, i*32 + j*4, 4)
+		}
+	}
+
+
+	// const witness = unstringifyBigInts(stringifyBigInts(w));
+	return wBuff;
+}
+
+