js-stellar-base/src/numbers/index.js

  1. import { XdrLargeInt } from './xdr_large_int';
  3. export { Uint128 } from './uint128';
  4. export { Uint256 } from './uint256';
  5. export { Int128 } from './int128';
  6. export { Int256 } from './int256';
  7. export { ScInt } from './sc_int';
  8. export { XdrLargeInt };
  10. /**
  11.  * Transforms an opaque {@link xdr.ScVal} into a native bigint, if possible.
  12.  *
  13.  * If you then want to use this in the abstractions provided by this module,
  14.  * you can pass it to the constructor of {@link XdrLargeInt}.
  15.  *
  16.  * @example
  17.  * let scv = contract.call("add", x, y); // assume it returns an xdr.ScVal
  18.  * let bigi = scValToBigInt(scv);
  19.  *
  20.  * new ScInt(bigi);               // if you don't care about types, and
  21.  * new XdrLargeInt('i128', bigi); // if you do
  22.  *
  23.  * @param {xdr.ScVal} scv - the raw XDR value to parse into an integer
  24.  * @returns {bigint} the native value of this input value
  25.  *
  26.  * @throws {TypeError} if the `scv` input value doesn't represent an integer
  27.  */
  28. export function scValToBigInt(scv) {
  29.   const scIntType = XdrLargeInt.getType(scv.switch().name);
  31.   switch (scv.switch().name) {
  32.     case 'scvU32':
  33.     case 'scvI32':
  34.       return BigInt(scv.value());
  36.     case 'scvU64':
  37.     case 'scvI64':
  38.       return new XdrLargeInt(scIntType, scv.value()).toBigInt();
  40.     case 'scvU128':
  41.     case 'scvI128':
  42.       return new XdrLargeInt(scIntType, [
  43.         scv.value().lo(),
  44.         scv.value().hi()
  45.       ]).toBigInt();
  47.     case 'scvU256':
  48.     case 'scvI256':
  49.       return new XdrLargeInt(scIntType, [
  50.         scv.value().loLo(),
  51.         scv.value().loHi(),
  52.         scv.value().hiLo(),
  53.         scv.value().hiHi()
  54.       ]).toBigInt();
  56.     default:
  57.       throw TypeError(`expected integer type, got ${scv.switch()}`);
  58.   }
  59. }