SyntaxError: "Cannot use import statement outside a module" - JavaScript in Python

Question

Problem Statement

I am trying to run a JavaScript code inside Python using stpyv8. However, I am getting the following error:

Traceback (most recent call last):
  File "/home/bobby/uni_balances_stpyv8/main.py", line 4, in <module>
    output = ctxt.eval("""
SyntaxError: SyntaxError: Cannot use import statement outside a module (  @ 3 : 0 )  -> import { JSBI } from "@uniswap/sdk";

I do have a package.json file and my hunch is that the Python code isn't considering the json file because the error above is actually solved by the package.json file Fixing module error in JS:

{
  "type": "module",
  "devDependencies": {
    "@babel/cli": "^7.19.3",
    "@babel/core": "^7.20.2",
    "@babel/preset-env": "^7.20.2"
  },
  "dependencies": {
    "@uniswap/sdk": "^3.0.3",
    "ethers": "^5.7.2"
  }
}

I do have package.json

The JavaScript does run and outputs the following:

Here is the JavaScript file:

import { JSBI } from "@uniswap/sdk";
import { ethers } from 'ethers';
import * as fs from 'fs';

    // ERC20 json abi file
let ERC20Abi = fs.readFileSync('Erc20.json');
const ERC20 = JSON.parse(ERC20Abi);

    // V3 pool abi json file
let pool = fs.readFileSync('V3PairAbi.json');
const IUniswapV3PoolABI = JSON.parse(pool);

    // V3 factory abi json
let facto = fs.readFileSync('V3factory.json');
const IUniswapV3FactoryABI = JSON.parse(facto);

let NFT = fs.readFileSync('UniV3NFT.json');
const IUniswapV3NFTmanagerABI = JSON.parse(NFT);

const provider = new ethers.providers.JsonRpcProvider(ALCHEMY_API_ID)

    // V3 standard addresses (different for celo)
const factory = "0x1F98431c8aD98523631AE4a59f267346ea31F984";
const NFTmanager = "0xC36442b4a4522E871399CD717aBDD847Ab11FE88";

async function getData(tokenID){
    let FactoryContract = new ethers.Contract(factory, IUniswapV3FactoryABI, provider);

    let NFTContract =  new ethers.Contract(NFTmanager, IUniswapV3NFTmanagerABI, provider);
    let position = await NFTContract.positions(tokenID);
    
    let token0contract =  new ethers.Contract(position.token0, ERC20, provider);
    let token1contract =  new ethers.Contract(position.token1, ERC20, provider);
    let token0Decimal = await token0contract.decimals();
    let token1Decimal = await token1contract.decimals();
    
    let token0sym = await token0contract.symbol();
    let token1sym = await token1contract.symbol();
    
    let V3pool = await FactoryContract.getPool(position.token0, position.token1, position.fee);
    let poolContract = new ethers.Contract(V3pool, IUniswapV3PoolABI, provider);

    let slot0 = await poolContract.slot0();

    
    let pairName = token0sym +"/"+ token1sym;
    
    let dict = {"SqrtX96" : slot0.sqrtPriceX96.toString(), "Pair": pairName, "T0d": token0Decimal, "T1d": token1Decimal, "tickLow": position.tickLower, "tickHigh": position.tickUpper, "liquidity": position.liquidity.toString()}

    return dict
}


const Q96 = JSBI.exponentiate(JSBI.BigInt(2), JSBI.BigInt(96));
const MIN_TICK = -887272;
const MAX_TICK = 887272;

function getTickAtSqrtRatio(sqrtPriceX96){
    let tick = Math.floor(Math.log((sqrtPriceX96/Q96)**2)/Math.log(1.0001));
    return tick;
}

async function getTokenAmounts(liquidity,sqrtPriceX96,tickLow,tickHigh,token0Decimal,token1Decimal){
    let sqrtRatioA = Math.sqrt(1.0001**tickLow).toFixed(18);
    let sqrtRatioB = Math.sqrt(1.0001**tickHigh).toFixed(18);
    let currentTick = getTickAtSqrtRatio(sqrtPriceX96);
    let sqrtPrice = sqrtPriceX96 / Q96;
    let amount0wei = 0;
    let amount1wei = 0;
    if(currentTick <= tickLow){
        amount0wei = Math.floor(liquidity*((sqrtRatioB-sqrtRatioA)/(sqrtRatioA*sqrtRatioB)));
    }
    if(currentTick > tickHigh){
        amount1wei = Math.floor(liquidity*(sqrtRatioB-sqrtRatioA));
    }
    if(currentTick >= tickLow && currentTick < tickHigh){ 
        amount0wei = Math.floor(liquidity*((sqrtRatioB-sqrtPrice)/(sqrtPrice*sqrtRatioB)));
        amount1wei = Math.floor(liquidity*(sqrtPrice-sqrtRatioA));
    }
    
    let amount0Human = (amount0wei/(10**token0Decimal)).toFixed(token0Decimal);
    let amount1Human = (amount1wei/(10**token1Decimal)).toFixed(token1Decimal);

    console.log("Amount Token0 wei: "+amount0wei);
    console.log("Amount Token1 wei: "+amount1wei);
    console.log("Amount Token0 : "+amount0Human);
    console.log("Amount Token1 : "+amount1Human);
    return [amount0wei, amount1wei]
}

async function start(positionID){
    let data = await getData(positionID);
    let tokens = await getTokenAmounts(data.liquidity, data.SqrtX96, data.tickLow, data.tickHigh, data.T0d, data.T1d);
}

start(273381)
// Also it can be used without the position data if you pull the data it will work for any range
getTokenAmounts(12558033400096537032, 20259533801624375790673555415)

Python3 code:

import STPyV8

with STPyV8.JSContext() as ctxt:
  output = ctxt.eval("""

import { JSBI } from "@uniswap/sdk";
import { ethers } from 'ethers';
import * as fs from 'fs';

    // ERC20 json abi file
let ERC20Abi = fs.readFileSync('Erc20.json');
const ERC20 = JSON.parse(ERC20Abi);

    // V3 pool abi json file
let pool = fs.readFileSync('V3PairAbi.json');
const IUniswapV3PoolABI = JSON.parse(pool);

    // V3 factory abi json
let facto = fs.readFileSync('V3factory.json');
const IUniswapV3FactoryABI = JSON.parse(facto);

let NFT = fs.readFileSync('UniV3NFT.json');
const IUniswapV3NFTmanagerABI = JSON.parse(NFT);

const provider = new ethers.providers.JsonRpcProvider("https://eth-mainnet.g.alchemy.com/v2/fRrLGBzCur7V6wCQjGRPdtmTUQzjCk2F")

    // V3 standard addresses (different for celo)
const factory = "0x1F98431c8aD98523631AE4a59f267346ea31F984";
const NFTmanager = "0xC36442b4a4522E871399CD717aBDD847Ab11FE88";

async function getData(tokenID){
    let FactoryContract = new ethers.Contract(factory, IUniswapV3FactoryABI, provider);

    let NFTContract =  new ethers.Contract(NFTmanager, IUniswapV3NFTmanagerABI, provider);
    let position = await NFTContract.positions(tokenID);
    
    let token0contract =  new ethers.Contract(position.token0, ERC20, provider);
    let token1contract =  new ethers.Contract(position.token1, ERC20, provider);
    let token0Decimal = await token0contract.decimals();
    let token1Decimal = await token1contract.decimals();
    
    let token0sym = await token0contract.symbol();
    let token1sym = await token1contract.symbol();
    
    let V3pool = await FactoryContract.getPool(position.token0, position.token1, position.fee);
    let poolContract = new ethers.Contract(V3pool, IUniswapV3PoolABI, provider);

    let slot0 = await poolContract.slot0();

    
    let pairName = token0sym +"/"+ token1sym;
    
    let dict = {"SqrtX96" : slot0.sqrtPriceX96.toString(), "Pair": pairName, "T0d": token0Decimal, "T1d": token1Decimal, "tickLow": position.tickLower, "tickHigh": position.tickUpper, "liquidity": position.liquidity.toString()}

    return dict
}


const Q96 = JSBI.exponentiate(JSBI.BigInt(2), JSBI.BigInt(96));
const MIN_TICK = -887272;
const MAX_TICK = 887272;

function getTickAtSqrtRatio(sqrtPriceX96){
    let tick = Math.floor(Math.log((sqrtPriceX96/Q96)**2)/Math.log(1.0001));
    return tick;
}

async function getTokenAmounts(liquidity,sqrtPriceX96,tickLow,tickHigh,token0Decimal,token1Decimal){
    let sqrtRatioA = Math.sqrt(1.0001**tickLow).toFixed(18);
    let sqrtRatioB = Math.sqrt(1.0001**tickHigh).toFixed(18);
    let currentTick = getTickAtSqrtRatio(sqrtPriceX96);
    let sqrtPrice = sqrtPriceX96 / Q96;
    let amount0wei = 0;
    let amount1wei = 0;
    if(currentTick <= tickLow){
        amount0wei = Math.floor(liquidity*((sqrtRatioB-sqrtRatioA)/(sqrtRatioA*sqrtRatioB)));
    }
    if(currentTick > tickHigh){
        amount1wei = Math.floor(liquidity*(sqrtRatioB-sqrtRatioA));
    }
    if(currentTick >= tickLow && currentTick < tickHigh){ 
        amount0wei = Math.floor(liquidity*((sqrtRatioB-sqrtPrice)/(sqrtPrice*sqrtRatioB)));
        amount1wei = Math.floor(liquidity*(sqrtPrice-sqrtRatioA));
    }
    
    let amount0Human = (amount0wei/(10**token0Decimal)).toFixed(token0Decimal);
    let amount1Human = (amount1wei/(10**token1Decimal)).toFixed(token1Decimal);

    console.log("Amount Token0 wei: "+amount0wei);
    console.log("Amount Token1 wei: "+amount1wei);
    console.log("Amount Token0 : "+amount0Human);
    console.log("Amount Token1 : "+amount1Human);
    return [amount0wei, amount1wei]
}

async function start(positionID){
    let data = await getData(positionID);
    let tokens = await getTokenAmounts(data.liquidity, data.SqrtX96, data.tickLow, data.tickHigh, data.T0d, data.T1d);
}

start(273381)
// Also it can be used without the position data if you pull the data it will work for any range
getTokenAmounts(12558033400096537032, 20259533801624375790673555415)
  """
  )

output = ctxt.eval()
print(output())

Again going back to my hunch, is it possible that Python isn't able to recognize the package.json in my project folder?

I get that this may be an interesting problem in its own right, but in terms of a practical solution create a self-contained JS bundle with webpack or rollup and call it a day. — Jared Smith, Nov 21 '22 at 18:23
Thanks @JaredSmith. I am not sure what is meant by "self-contained JS bundle with webpack or rollup and call it a day." Do you have some resources I can read? I am not set on my solution and am open to any solution. I just need to get the output from JS into Python somehow. — beeeZeee, Nov 21 '22 at 19:24
https://webpack.js.org/concepts/. It's a CLI program that takes a JS application, resolves all the dependencies, and concatenates it into a single self-contained source file, much like a native code compiler can produce a statically linked binary executable. It's frequently used in JS-land because a given client-side JS app will have hundreds of dependencies, you don't typically want a browser making hundreds of HTTP requests. — Jared Smith, Nov 22 '22 at 14:42
I dont think this is possible, i.e. you cannot use `require` or `import` with your library based on pyv8. https://stackoverflow.com/a/9850251/258174 — morganney, Nov 26 '22 at 14:53

score 2 · Answer 1 · answered Nov 26 '22 at 02:58

SyntaxError: "Cannot use import statement outside a module"

this error is clear, you are using import statement in the wrong place. for example, create a test.js file and add only this line of code

 import fs from "fs";

then execute the file with node test.js. you will get this error.

Because when you execute the file with node command it is node.js environment where it supports commonjs not es6 modules.

one solution is to change the file extension from js to mjs. if you change the test.js to test.mjs and run node test.mjs your code will execute successfully.

Second solution is instead of import use this syntax.

 const ethers = require('ethers');

Third solution is add this to package.json file

 "type": "module"

I have tried the require route, but it complains that "ethers" is not defined. I believe you do need the import function here. (Please see my comment to the below answer). — beeeZeee, Nov 27 '22 at 14:14

score 0 · Answer 2 · answered Nov 24 '22 at 04:40

0

I think you need to do what is described in nodejs-convert-from-import-to-require

so change :

import { JSBI } from "@uniswap/sdk";
import { ethers } from 'ethers';
import * as fs from 'fs';

to

const { JSBI } = require ("@uniswap/sdk")
const { ethers } = require ('ethers')
const fs = require('fs')

answered Nov 24 '22 at 04:40

wrbp

870
1
3
9

But now I am getting a `required not defined` error: ` Traceback (most recent call last): File "/home/bobby/uni_balances_stpyv8/main.py", line 4, in output = ctxt.eval(""" ReferenceError: ReferenceError: require is not defined ( @ 3 : 17 ) -> const { JSBI } = require ("@uniswap/sdk") ` – beeeZeee Nov 24 '22 at 13:50

SyntaxError: "Cannot use import statement outside a module" - JavaScript in Python

Problem Statement

2 Answers2

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