@technobuddha/library/src/decode-text.test.ts

A large library of useful functions

// cspell:ignore ΑΒΓΔΕΖ, ΑΒΓΔ

import { decodeText } from './decode-text.ts';
import { replacementCharacter } from './unicode.ts';

describe('decodeText', () => {
  test('should not change ASCII', () => {
    expect(decodeText([0x61, 0x62, 0x63, 0x64, 0x65, 0x66])).toBe('abcdef');
    expect(decodeText([0x00, 0x01, 0x02, 0x03, 0x7f])).toBe('\u0000\u0001\u0002\u0003\u007F');
  });

  test('two byte ut8 sequences', () => {
    expect(decodeText([0xc2, 0xbc, 0xc2, 0xbd, 0xc2, 0xbe])).toBe('¼½¾');
    expect(decodeText([0xce, 0x91, 0xce, 0x92, 0xce, 0x93, 0xce, 0x94])).toBe('ΑΒΓΔ');
  });

  test('three byte ut8 sequences', () => {
    expect(decodeText([0xe2, 0x99, 0x80, 0xe2, 0x99, 0x82])).toBe('♀♂');
    expect(decodeText([0xea, 0xad, 0x93, 0xea, 0xad, 0x94, 0xea, 0xad, 0x95])).toBe('ꭓꭔꭕ');
  });

  test('four byte ut8 sequences', () => {
    expect(
      decodeText([0xf0, 0x9f, 0x98, 0x80, 0xf0, 0x9f, 0x98, 0x81, 0xf0, 0x9f, 0x98, 0x82]),
    ).toBe('😀😁😂');
    expect(
      decodeText([0xf0, 0x9d, 0x90, 0x80, 0xf0, 0x9d, 0x90, 0x81, 0xf0, 0x9d, 0x90, 0x82]),
    ).toBe('𝐀𝐁𝐂');
  });

  test('should trap bad surrogate pairs', () => {
    expect(decodeText([0xc0])).toBe(replacementCharacter);
    expect(decodeText([0xc0, 0x00])).toBe(replacementCharacter);
    expect(decodeText([0xe0])).toBe(replacementCharacter);
    expect(decodeText([0xe0, 0x80])).toBe(replacementCharacter);
    expect(decodeText([0xe0, 0x00])).toBe(replacementCharacter);
    expect(decodeText([0xe0, 0x80, 0x00])).toBe(replacementCharacter);
    expect(decodeText([0xf0])).toBe(replacementCharacter);
    expect(decodeText([0xf0, 0x80])).toBe(replacementCharacter);
    expect(decodeText([0xf0, 0x00])).toBe(replacementCharacter);
    expect(decodeText([0xf0, 0x80, 0x80])).toBe(replacementCharacter);
    expect(decodeText([0xf0, 0x00, 0x80])).toBe(replacementCharacter);
    expect(decodeText([0xf0, 0x80, 0x80, 0x00])).toBe(replacementCharacter);
    expect(decodeText([0xf4, 0xbf, 0xbf, 0xbf])).toBe(replacementCharacter);
    expect(decodeText([0xf9])).toBe(replacementCharacter);
  });

  test('call with Typed Array', () => {
    expect(decodeText(new Uint8Array([0x61, 0x62, 0x63, 0x64, 0x65, 0x66]))).toBe('abcdef');
  });
});