Error while parsing exponent

[FunnySaltyFish]

Currently, the library seems cannot parse exponent numbers correctly, like 1e5, 1.2e-4, 0.8e+5.
and, you might need to consider situations when the exponent num is incomplete, for example, for 1.2e5, when the exponent 5 is missing, there will be only 1.2e.

Test code(tokenize.test.ts):

describe('tokenizer extreme cases', () => {
  // 1e3
  it('incomplete expontional num', () => {
    expect(tokenize('1e3')).toEqual([
      {
        type: TokenType.Number,
        value: 1e3,
      },
    ]);
  });
});

Error:

      119 |         }
      120 |         default: {
    > 121 |           throw new SyntaxError(
          |                 ^
      122 |             `Unexpected character: "${char}" ` + `at position: ${context.index}`
      123 |           );
      124 |         }

      at Object.tokenize (src/tokenizer/tokenize.ts:121:17)

Relative code: function parseExponent(context: ParseContext).