Babel-plugin-transform-bigint NPM

babel-plugin-transform-bigint

Update: Now it can convert a code using BigInt into a code using JSBI (https://github.com/GoogleChromeLabs/jsbi). It will try to detect when an operator is used for bigints, not numbers. This will not work in many cases, so please use JSBI directly only if you know, that the code works only with bigints.

An example from https://github.com/GoogleChromeLabs/babel-plugin-transform-jsbi-to-bigint:

Input using native BigInts:

const a = BigInt(Number.MAX_SAFE_INTEGER);
const b = 2n;

a + b;
a - b;
a * b;
a / b;
a % b;
a ** b;
a << b;
a >> b;
a & b;
a | b;
a ^ b;

-a;
~a;

a === b;
a < b;
a <= b;
a > b;
a >= b;

a.toString();
Number(a);

Compiled output using JSBI:

const a = JSBI.BigInt(Number.MAX_SAFE_INTEGER);
const b = JSBI.BigInt(2);
JSBI.add(a, b);
JSBI.subtract(a, b);
JSBI.multiply(a, b);
JSBI.divide(a, b);
JSBI.remainder(a, b);
JSBI.exponentiate(a, b);
JSBI.leftShift(a, b);
JSBI.signedRightShift(a, b);
JSBI.bitwiseAnd(a, b);
JSBI.bitwiseOr(a, b);
JSBI.bitwiseXor(a, b);
JSBI.unaryMinus(a);
JSBI.bitwiseNot(a);
JSBI.equal(a, b);
JSBI.lessThan(a, b);
JSBI.lessThanOrEqual(a, b);
JSBI.greaterThan(a, b);
JSBI.greaterThanOrEqual(a, b);
a.toString();
JSBI.toNumber(a);

Playground:

Open https://babeljs.io/en/repl
Turn off all presets.
"Add plugin" @babel/babel-plugin-syntax-bigint
"Add plugin" babel-plugin-transform-bigint

¡ It is buggy !

Example:

Create a folder "example".
Create a file test.js:

// floor(log2(n)), n >= 1
function ilog2(n) {
  let i = 0n;
  while (n >= 2n**(2n**i)) {
    i += 1n;
  }
  let e = 0n;
  let t = 1n;
  while (i >= 0n) {
    let b = 2n**i;
    if (n >= t * 2n**b) {
      t *= 2n**b;
      e += b;
    }
    i -= 1n;
  }
  return e;
}

// floor(sqrt(S)), S >= 0, https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method
function sqrt(S) {
  let e = ilog2(S);
  if (e < 2n) {
    return 1n;
  }
  let f = e / 4n + 1n;
  let x = (sqrt(S / 2n**(f * 2n)) + 1n) * 2n**f;
  let xprev = x + 1n;
  while (xprev > x) {
    xprev = x;
    x = (x + S / x) / 2n;
  }
  return xprev;
}

function squareRoot(value, decimalDigits) {
  return (sqrt(BigInt(value) * 10n**(BigInt(decimalDigits) * 2n + 2n)) + 5n).toString();
}

Use babel:

npm init
npm install --save https://github.com/Yaffle/babel-plugin-transform-bigint
npm install --save-dev @babel/core @babel/cli
npm install jsbi --save
npm install --global http-server
npx babel --plugins=babel-plugin-transform-bigint test.js > test-transformed.js
http-server -p 8081

Comment out the next line in test-transformed.js:

import JSBI from "./jsbi.mjs";

Create a file test.html.

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8" />
  <script src="./node_modules/jsbi/dist/jsbi-umd.js"></script>
  <script src="test-transformed.js"></script>
  <script>
    document.addEventListener("DOMContentLoaded", function (event) {
      const form = document.querySelector("form");
      form.oninput = function () {
        const value = form.value.value;
        const digits = Number(form.digits.value);
        const s = squareRoot(value, digits);
        // IE 11 does not support <output> element, so `form.output.value = "value";` is not working.
        form.querySelector("output").textContent = '√' + value +  ' ≈ ' + s.slice(0, 0 - digits - 1) + '.' + s.slice(0 - digits - 1, -1) + '…';
      };
      form.oninput();
    }, false);
  </script>
  <style>
    output {
      overflow-wrap: break-word;
    }
  </style>
</head>
<body>
  <form>
    <div>
      <label for="value">Value:</label>
      <input id="value" name="value" type="number" min="2" step="1" value="2" />
    </div>
    <div>
      <label for="digits">Number of decimal digits:</label>
      <input id="digits" name="digits" type="number" min="1" step="1" value="100" />
    </div>
    <div>
      <output id="output" name="output" for="value digits" tabindex="0"></output>
    </div>
  </form>
</body>
</html>