caseConvert.test.ts

import {
  objectToCamel,
  objectToSnake,
  toSnake,
  ToCamel,
  ToSnake,
  toCamel,
  ObjectToSnake,
  toPascal,
  objectToPascal,
} from '../src/caseConvert';

describe('Property name converter', () => {
  it('converts to camelCase', () => {
    const testToCamel = objectToCamel({
      hello_world: 'helloWorld',
      a_number: 5,
      an_array: [1, 2, 4],
      null_object: null,
      undef_object: undefined,
      an_array_of_objects: [{ a_b: 'ab', a_c: 'ac' }],
      an_object: {
        a_1: 'a1',
        a_2: 'a2',
        a_3: {
          b_4: 'b4',
        },
      },
    });

    expect('helloWorld' in testToCamel).toStrictEqual(true);
    expect('hello_world' in testToCamel).not.toStrictEqual(true);
    expect(testToCamel.aNumber).toEqual(5);
    expect(testToCamel.helloWorld).toEqual('helloWorld');
    expect(testToCamel.anArray).toEqual([1, 2, 4]);
    expect(testToCamel.nullObject).toBeNull();
    expect(testToCamel.undefObject).toBeUndefined();
    expect(testToCamel.anArrayOfObjects[0].aB).toEqual('ab');
    expect(testToCamel.anArrayOfObjects[0].aC).toEqual('ac');
    expect(testToCamel.anObject.a1).toEqual('a1');
    expect(testToCamel.anObject.a2).toEqual('a2');
    expect(testToCamel.anObject.a3.b4).toEqual('b4');
  });

  it('converts to snake_case', () => {
    const testToSnake = objectToSnake({
      helloWorld: 'helloWorld',
      aNumber: 5,
      anArray: [1, 2, 4],
      nullObject: null,
      undefObject: undefined,
      anArrayOfObjects: [{ aB: 'ab', aC: 'ac' }],
      anObject: {
        A1: 'a_1',
        A2: 'a_2',
        A3: {
          B4: 'b_4',
        },
      },
    });

    expect('helloWorld' in testToSnake).toStrictEqual(false);
    expect('hello_world' in testToSnake).toStrictEqual(true);
    expect(testToSnake.a_number).toEqual(5);
    expect(testToSnake.hello_world).toEqual('helloWorld');
    expect(testToSnake.an_array).toEqual([1, 2, 4]);
    expect(testToSnake.null_object).toBeNull();
    expect(testToSnake.undef_object).toBeUndefined();
    expect(testToSnake.an_array_of_objects[0].a_b).toEqual('ab');
    expect(testToSnake.an_array_of_objects[0].a_c).toEqual('ac');
    expect(testToSnake.an_object.a1).toEqual('a_1');
    expect(testToSnake.an_object.a2).toEqual('a_2');
    expect(testToSnake.an_object.a3.b4).toEqual('b_4');
  });

  it('converts to PascalCase from camelCase', () => {
    const testToPascal = objectToPascal({
      helloWorld: 'helloWorld',
      aNumber: 5,
      anArray: [1, 2, 4],
      nullObject: null,
      undefObject: undefined,
      anArrayOfObjects: [{ aB: 'ab', aC: 'ac' }],
      anObject: {
        A1: 'a_1',
        A2: 'a_2',
        A3: {
          B4: 'b_4',
        },
      },
    });

    expect('helloWorld' in testToPascal).toStrictEqual(false);
    expect('HelloWorld' in testToPascal).toStrictEqual(true);
    expect(testToPascal.ANumber).toEqual(5);
    expect(testToPascal.HelloWorld).toEqual('helloWorld');
    expect(testToPascal.AnArray).toEqual([1, 2, 4]);
    expect(testToPascal.NullObject).toBeNull();
    expect(testToPascal.UndefObject).toBeUndefined();
    expect(testToPascal.AnArrayOfObjects[0].AB).toEqual('ab');
    expect(testToPascal.AnArrayOfObjects[0].AC).toEqual('ac');
    expect(testToPascal.AnObject.A1).toEqual('a_1');
    expect(testToPascal.AnObject.A2).toEqual('a_2');
    expect(testToPascal.AnObject.A3.B4).toEqual('b_4');
  });

  it('converts to PascalCase from snake_case', () => {
    const testToPascal = objectToPascal({
      hello_world: 'helloWorld',
      a_number: 5,
      an_array: [1, 2, 4],
      null_object: null,
      undef_object: undefined,
      an_array_of_objects: [{ a_b: 'ab', a_c: 'ac' }],
      an_object: {
        a_1: 'a1',
        a_2: 'a2',
        a_3: {
          b_4: 'b4',
        },
      },
    });

    expect('helloWorld' in testToPascal).toStrictEqual(false);
    expect('HelloWorld' in testToPascal).toStrictEqual(true);
    expect(testToPascal.ANumber).toEqual(5);
    expect(testToPascal.HelloWorld).toEqual('helloWorld');
    expect(testToPascal.AnArray).toEqual([1, 2, 4]);
    expect(testToPascal.NullObject).toBeNull();
    expect(testToPascal.UndefObject).toBeUndefined();
    expect(testToPascal.AnArrayOfObjects[0].AB).toEqual('ab');
    expect(testToPascal.AnArrayOfObjects[0].AC).toEqual('ac');
    expect(testToPascal.AnObject.A1).toEqual('a1');
    expect(testToPascal.AnObject.A2).toEqual('a2');
    expect(testToPascal.AnObject.A3.B4).toEqual('b4');
  });
});

describe('Regular expressions', () => {
  it('converts to camelCase', () => {
    expect(toCamel('hello_world')).toEqual('helloWorld');
    expect(toCamel('the_quick_brown_fox_jumps_over_the_lazy_dog')).toEqual(
      'theQuickBrownFoxJumpsOverTheLazyDog',
    );
    expect(toCamel('abc')).toEqual('abc');
    expect(toCamel('abc')).toEqual('abc');
    expect(toCamel('a_b_c')).toEqual('aBC');
    expect(toCamel('ab_c')).toEqual('abC');
    expect(toCamel('a_b')).toEqual('aB');
    expect(toCamel('a_b')).toEqual('aB');
    expect(toCamel('abc_d')).toEqual('abcD');
    expect(toCamel('abc_d')).toEqual('abcD');
    expect(toCamel('ab_cde')).toEqual('abCde');
    expect(toCamel('abc_d_e_f')).toEqual('abcDEF');
    expect(toCamel('ab_cdef_g')).toEqual('abCdefG');
    expect(toCamel('ab_cd_e_f_gh')).toEqual('abCdEFGh');
    expect(toCamel('A')).toEqual('a');
    expect(toCamel('a1')).toEqual('a1');
    expect(toCamel('a_1')).toEqual('a1');
    expect(toCamel('a_1c_2d')).toEqual('a1c2d');
    expect(toCamel('ab_1c_2_d')).toEqual('ab1c2D');
    expect(toCamel('ab_1c_2d')).toEqual('ab1c2d');
    expect(toCamel('ab_25')).toEqual('ab25');
    expect(toCamel('abc_e25_d50')).toEqual('abcE25D50');
    expect(toCamel('abc_25_d50')).toEqual('abc25D50');
    expect(toCamel('abc_25_a50')).toEqual('abc25A50');
  });

  it('converts from PascalCase to camelCase', () => {
    expect(toCamel('HelloWorld')).toEqual('helloWorld');
    expect(toCamel('helloWorld')).toEqual('helloWorld');
    expect(toCamel('8HelloWorld')).toEqual('8HelloWorld');
    expect(toCamel('Abc')).toEqual('abc');
    expect(toCamel('ABC')).toEqual('aBC');
    expect(toCamel('AbC')).toEqual('abC');
    expect(toCamel('AB')).toEqual('aB');
    expect(toCamel('AbcD')).toEqual('abcD');
    expect(toCamel('AbCde')).toEqual('abCde');
    expect(toCamel('AbcDEF')).toEqual('abcDEF');
    expect(toCamel('AbCdefG')).toEqual('abCdefG');
    expect(toCamel('AbCdEFGh')).toEqual('abCdEFGh');
    expect(toCamel('A')).toEqual('a');
    expect(toCamel('A1')).toEqual('a1');
    expect(toCamel('A1c2d')).toEqual('a1c2d');
    expect(toCamel('Ab1c2D')).toEqual('ab1c2D');
    expect(toCamel('Ab1c2d')).toEqual('ab1c2d');
    expect(toCamel('Ab25')).toEqual('ab25');
    expect(toCamel('AbcE25D50')).toEqual('abcE25D50');
    expect(toCamel('Abc25D50')).toEqual('abc25D50');
    expect(toCamel('Abc25A50')).toEqual('abc25A50');
  });

  it('converts to PascalCase', () => {
    expect(toPascal('hello_world')).toEqual('HelloWorld');
    expect(toPascal('the_quick_brown_fox_jumps_over_the_lazy_dog')).toEqual(
      'TheQuickBrownFoxJumpsOverTheLazyDog',
    );
    expect(toPascal('abc')).toEqual('Abc');
    expect(toPascal('a_b_c')).toEqual('ABC');
    expect(toPascal('ab_c')).toEqual('AbC');
    expect(toPascal('a_b')).toEqual('AB');
    expect(toPascal('a_b')).toEqual('AB');
    expect(toPascal('abc_d')).toEqual('AbcD');
    expect(toPascal('abc_d')).toEqual('AbcD');
    expect(toPascal('ab_cde')).toEqual('AbCde');
    expect(toPascal('abc_d_e_f')).toEqual('AbcDEF');
    expect(toPascal('ab_cdef_g')).toEqual('AbCdefG');
    expect(toPascal('ab_cd_e_f_gh')).toEqual('AbCdEFGh');
    expect(toPascal('A')).toEqual('A');
    expect(toPascal('a1')).toEqual('A1');
    expect(toPascal('a_1')).toEqual('A1');
    expect(toPascal('a_1c_2d')).toEqual('A1c2d');
    expect(toPascal('ab_1c_2_d')).toEqual('Ab1c2D');
    expect(toPascal('ab_1c_2d')).toEqual('Ab1c2d');
    expect(toPascal('ab_25')).toEqual('Ab25');
    expect(toPascal('abc_e25_d50')).toEqual('AbcE25D50');
    expect(toPascal('abc_25_d50')).toEqual('Abc25D50');
    expect(toPascal('abc_25_a50')).toEqual('Abc25A50');
  });

  it('converts to snake case', () => {
    expect(toSnake('helloWorld')).toEqual('hello_world');
    expect(toSnake('theQuickBrownFoxJumpsOverTheLazyDog')).toEqual(
      'the_quick_brown_fox_jumps_over_the_lazy_dog',
    );
    expect(toSnake('Abc')).toEqual('abc');
    expect(toSnake('abc')).toEqual('abc');
    expect(toSnake('ABC')).toEqual('a_b_c');
    expect(toSnake('abC')).toEqual('ab_c');
    expect(toSnake('AB')).toEqual('a_b');
    expect(toSnake('aB')).toEqual('a_b');
    expect(toSnake('AbcD')).toEqual('abc_d');
    expect(toSnake('abcD')).toEqual('abc_d');
    expect(toSnake('abCde')).toEqual('ab_cde');
    expect(toSnake('abcDEF')).toEqual('abc_d_e_f');
    expect(toSnake('abCdefG')).toEqual('ab_cdef_g');
    expect(toSnake('AbCdEFGh')).toEqual('ab_cd_e_f_gh');
    expect(toSnake('A')).toEqual('a');
    expect(toSnake('A1')).toEqual('a1');
    expect(toSnake('a1')).toEqual('a_1');
    expect(toSnake('a1c2d')).toEqual('a_1c_2d');
    expect(toSnake('ab1c2D')).toEqual('ab_1c_2_d');
    expect(toSnake('ab1c2d')).toEqual('ab_1c_2d');
    expect(toSnake('ab25')).toEqual('ab_25');
    expect(toSnake('abcE25D50')).toEqual('abc_e25_d50');
    expect(toSnake('abc25D50')).toEqual('abc_25_d50');
    expect(toSnake('abc25A50')).toEqual('abc_25_a50');
  });
});

type NotAny<T> = T[] extends true[] ? T : T[] extends false[] ? T : never;
type AssertEqual<T, Expected> = NotAny<
  T extends Expected ? (Expected extends T ? true : false) : false
>;

type T0 = ToCamel<'hello_world'>;
const _t0: AssertEqual<T0, 'helloWorld'> = true;

type T1 = ToSnake<'helloWorld'>;
const _s1: AssertEqual<T1, 'hello_world'> = true;
type T2 = ToSnake<'theQuickBrownFoxJumpsOver'>;
const _s2: AssertEqual<T2, 'the_quick_brown_fox_jumps_over'> = true;
type T3 = ToSnake<'abc'>;
const _s3: AssertEqual<T3, 'abc'> = true;
type T4 = ToSnake<'Abc'>;
const _s4: AssertEqual<T4, 'abc'> = true;
type T5 = ToSnake<'ABC'>;
const _s5: AssertEqual<T5, 'a_b_c'> = true;
type T6 = ToSnake<'abC'>;
const _s6: AssertEqual<T6, 'ab_c'> = true;
type T7 = ToSnake<'ABc'>;
const _s7: AssertEqual<T7, 'a_bc'> = true;
type T8 = ToSnake<'AB'>;
const _s8: AssertEqual<T8, 'a_b'> = true;
type T9 = ToSnake<'aB'>;
const _s9: AssertEqual<T9, 'a_b'> = true;
type T10 = ToSnake<'AbcD'>;
const _s10: AssertEqual<T10, 'abc_d'> = true;
type T11 = ToSnake<'abcD'>;
const _s11: AssertEqual<T11, 'abc_d'> = true;
type T12 = ToSnake<'abCde'>;
const _s12: AssertEqual<T12, 'ab_cde'> = true;
type T13 = ToSnake<'abcDEF'>;
const _s13: AssertEqual<T13, 'abc_d_e_f'> = true;
type T14 = ToSnake<'abCdefG'>;
const _s14: AssertEqual<T14, 'ab_cdef_g'> = true;
type T15 = ToSnake<'AbCdEFGh'>;
const _s15: AssertEqual<T15, 'ab_cd_e_f_gh'> = true;
type T16 = ToSnake<'A'>;
const _s16: AssertEqual<T16, 'a'> = true;
type T161 = ToSnake<'A1'>;
const _s161: AssertEqual<T161, 'a1'> = true;
type T17 = ToSnake<'a1c2d'>;
const _s17: AssertEqual<T17, 'a_1c_2d'> = true;
type T18 = ToSnake<'ab1c2D'>;
const _s18: AssertEqual<T18, 'ab_1c_2_d'> = true;
type T19 = ToSnake<'ab1c2d'>;
const _s19: AssertEqual<T19, 'ab_1c_2d'> = true;
type T20 = ToSnake<'abc25'>;
const _s20: AssertEqual<T20, 'abc_25'> = true;
type T21 = ToSnake<'abcE25D50'>;
const _s21: AssertEqual<T21, 'abc_e25_d50'> = true;
type T22 = ToSnake<'abc25D50'>;
const _s22: AssertEqual<T22, 'abc_25_d50'> = true;
type T23 = ToSnake<'abc25A50'>;
const _s23: AssertEqual<T23, 'abc_25_a50'> = true;
type T25 = ToSnake<'a'>;
const _s25: AssertEqual<T25, 'a'> = true;

interface I24 {
  optionalObject?: {
    aProp: string;
    bProp:
      | {
          cProp: string;
        }
      | undefined;
  };
}

interface I242 {
  optional_object?: {
    a_prop: string;
    b_prop:
      | {
          c_prop: string;
        }
      | undefined;
  };
}

const _c24: I24 = {
  optionalObject: {
    aProp: 'a',
    bProp: {
      cProp: 'c',
    },
  },
};
const _c242: I242 = objectToSnake(_c24);

const _s24: AssertEqual<I242, ObjectToSnake<I24>> = true;

type T26 = ToCamel<'HelloWorld'>;
const _t26: AssertEqual<T26, 'helloWorld'> = true;
type T27 = ToCamel<'helloWorld'>;
const _t27: AssertEqual<T27, 'helloWorld'> = true;
type T28 = ToCamel<'8HelloWorld'>;
const _t28: AssertEqual<T28, '8HelloWorld'> = true;

interface I243 {
  nullable_object: { a_prop: string } | null;
}

const _c243: I243 = {
  nullable_object: {
    a_prop: 'a',
  },
};
interface I2432 {
  nullableObject: { aProp: string } | null;
}

const _c2432: I2432 = objectToCamel(_c243);

const _s243: AssertEqual<I243, ObjectToSnake<I2432>> = true;