parsec/src/test/parse.test.ts

import { describe, expect, test } from "bun:test";
import { Parse, ParseError } from "../index.ts";

describe(Parse.unknown, () => {
  test("returns the value as provided", () => {
    const val = Parse.unknown("hello");
    expect(val).toBe("hello");
  });
});

describe(Parse.string, () => {
  test("Parses strings", () => {
    expect(Parse.string("hello")).toBe("hello");
  });

  test("Throws an error when parsing a non-string", () => {
    const INVALID_VALUES = [null, undefined, 123, true, false, {}];

    for (const val of INVALID_VALUES) {
      expect(() => Parse.string(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.number, () => {
  test("Parses numbers", () => {
    expect(Parse.number(123)).toBe(123);
  });

  test("Throws an error when parsing a non-number", () => {
    const INVALID_VALUES = [null, undefined, "hello", true, false, {}];

    for (const val of INVALID_VALUES) {
      expect(() => Parse.number(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.boolean, () => {
  test("Parses booleans", () => {
    expect(Parse.boolean(true)).toBe(true);
    expect(Parse.boolean(false)).toBe(false);
  });

  test("Throws an error when parsing a non-boolean", () => {
    const INVALID_VALUES = [null, undefined, "hello", 123, {}];
    for (const val of INVALID_VALUES) {
      expect(() => Parse.boolean(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.bigint, () => {
  test("Parses bigints", () => {
    expect(Parse.bigint(BigInt(123))).toBe(BigInt(123));
  });

  test("Throws an error when parsing a non-bigint", () => {
    const INVALID_VALUES = [null, undefined, "hello", 123, true, false, {}];
    for (const val of INVALID_VALUES) {
      expect(() => Parse.bigint(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.symbol, () => {
  test("Parses symbols", () => {
    const symbol = Symbol("hello");
    expect(Parse.symbol(symbol)).toBe(symbol);
  });

  test("Throws an error when parsing a non-symbol", () => {
    const INVALID_VALUES = [null, undefined, "hello", 123, true, false, {}];

    for (const val of INVALID_VALUES) {
      expect(() => Parse.symbol(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.null, () => {
  test("Parses null", () => {
    expect(Parse.null(null)).toBe(null);
  });

  test("Throws an error when parsing a non-null", () => {
    const INVALID_VALUES = [undefined, "hello", 123, true, false, {}];
    for (const val of INVALID_VALUES) {
      expect(() => Parse.null(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.undefined, () => {
  test("Parses undefined", () => {
    expect(Parse.undefined(undefined)).toBe(undefined);
  });

  test("Throws an error when parsing a non-undefined", () => {
    const INVALID_VALUES = [null, "hello", 123, true, false, {}];

    for (const val of INVALID_VALUES) {
      expect(() => Parse.undefined(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.arrayOf, () => {
  test("Parses arrays of a specific type", () => {
    const arr = [1, 2, 3];
    expect(Parse.arrayOf(Parse.number)(arr)).toEqual(arr);
  });

  test("Throws an error when parsing a non-array", () => {
    expect(() => Parse.arrayOf(Parse.number)("hello")).toThrow(ParseError);
  });

  test("Throws an error when parsing an array with invalid values", () => {
    const INVALID_VALUES = [null, undefined, "hello", true, false, {}];
    for (const val of INVALID_VALUES) {
      const arr = [1, val, 3];
      expect(() => Parse.arrayOf(Parse.number)(arr)).toThrow(ParseError);
    }
  });
});

describe(Parse.shape, () => {
  test("Parses objects", () => {
    const obj = { name: "hello", age: 123 };
    const shape = { name: Parse.string, age: Parse.number };
    expect(Parse.shape(shape)(obj)).toEqual(obj);
  });

  test("Throws an error when parsing a non-object", () => {
    expect(() => Parse.shape({})("hello")).toThrow(ParseError);
  });

  test("Throws an error when parsing an object with invalid values", () => {
    const obj = { name: "hello", age: "world" };
    const shape = { name: Parse.string, age: Parse.number };
    expect(() => Parse.shape(shape)(obj)).toThrow(ParseError);
  });

  test("allows optional object entries", () => {
    const parseThing = Parse.shape({
      name: Parse.string,
      another: Parse.optional(Parse.string),
    });

    const result = parseThing({
      name: "hello",
    });

    expect(result).toEqual({
      name: "hello",
      another: undefined,
    });
  });

  test("allows nullable entries", () => {
    const parseThing = Parse.shape({
      name: Parse.string,
      another: Parse.nullable(Parse.string),
    });

    expect(parseThing({ name: "hello", another: null })).toEqual({
      name: "hello",
      another: null,
    });
  });

  test("nullable entries can accpet undefined when configured as such", () => {
    const parseThing = Parse.shape({
      name: Parse.string,
      another: Parse.nullable(Parse.string, true),
    });

    const obj = {
      name: "hello",
      another: undefined,
    };

    const result = parseThing(obj);

    expect(result).toEqual({
      name: "hello",
      another: null,
    });
  });

  test("optional entries can accpet null when configured as such", () => {
    const parseThing = Parse.shape({
      name: Parse.string,
      another: Parse.optional(Parse.string, true),
    });

    const obj = {
      name: "hello",
      another: null,
    };

    const result = parseThing(obj);

    expect(result).toEqual({
      name: "hello",
      another: undefined,
    });
  });

  test("throws when a required value is missing", () => {
    const parseThing = Parse.shape({
      name: Parse.string,
      another: Parse.optional(Parse.string),
    });

    expect(() => {
      parseThing({ another: "hello" });
    }).toThrow(ParseError);
  });
});

describe(Parse.enum, () => {
  test("Parses valid enum values", () => {
    const enumValues = ["hello", "world"] as const;
    expect(Parse.enum(enumValues)("hello")).toBe("hello");
  });

  test("Throws an error when parsing an invalid enum value", () => {
    const enumValues = ["hello", "world"] as const;
    expect(() => Parse.enum(enumValues)("invalid")).toThrow(ParseError);
  });
});

describe(Parse.regex, () => {
  test("Parses valid regex values", () => {
    expect(Parse.regex(/hello/)("hello")).toBe("hello");
  });

  test("Throws an error when parsing an invalid regex value", () => {
    expect(() => Parse.regex(/hello/)("world")).toThrow(ParseError);
  });
});

describe(Parse.optional, () => {
  test("Parses undefined values", () => {
    expect(Parse.optional(Parse.string)(undefined)).toBeUndefined();
  });

  test("Parses null values when configured", () => {
    expect(Parse.optional(Parse.string, true)(null)).toBeUndefined();
  });
});

describe(Parse.nullable, () => {
  test("Parses null values", () => {
    expect(Parse.nullable(Parse.string)(null)).toBeNull();
  });

  test("Parses undefined values when configured", () => {
    expect(Parse.nullable(Parse.string, true)(undefined)).toBeNull();
  });
});

describe(Parse.defaulted, () => {
  test("Parses uses a default value for undefined params", () => {
    expect(Parse.defaulted(Parse.string, "default!")(undefined)).toBe(
      "default!",
    );
  });
});

describe(Parse.nan, () => {
  test("Parses NaN", () => {
    expect(Parse.nan(Number.NaN)).toBe(Number.NaN);
  });

  test("Throws an error when parsing a non-NaN", () => {
    const INVALID_VALUES = [null, undefined, "hello", 123, true, false, {}];
    for (const val of INVALID_VALUES) {
      expect(() => Parse.nan(val)).toThrow(ParseError);
    }
  });
});

class TestClass { }

describe(Parse.instanceOf, () => {
  test("Parses instances of a class", () => {
    const testClass = new TestClass();
    expect(Parse.instanceOf(TestClass)(testClass)).toBe(testClass);
  });

  test("Throws an error when parsing a non-instance", () => {
    const INVALID_VALUES = [null, undefined, "hello", 123, true, false, {}];
    for (const val of INVALID_VALUES) {
      expect(() => Parse.instanceOf(TestClass)(val)).toThrow(ParseError);
    }
  });

  test("Throws an error when parsing an instance of a different class", () => {
    const testClass = new TestClass();
    expect(() => Parse.instanceOf(class AnotherClass { })(testClass)).toThrow(
      ParseError,
    );
  });
});

describe(Parse.oneOf, () => {
  test("Parses values that match one of the parsers", () => {
    const parsers = [Parse.string, Parse.number];
    expect(Parse.oneOf(parsers)("hello")).toEqual("hello");
  });

  test("Throws an error when parsing a value that doesn't match any parser", () => {
    const parsers = [Parse.string, Parse.number];
    const INVALID_VALUES = [null, undefined, true, false, {}];
    for (const val of INVALID_VALUES) {
      expect(() => Parse.oneOf(parsers)(val)).toThrow(ParseError);
    }
  });
});

describe(Parse.recordOf, () => {
  test("Parses records of a specific type", () => {
    const stringToString = Parse.recordOf(Parse.string, Parse.string);

    const rec = {
      key: "value",
      another: "another",
    };

    const badRec = {
      key: "value",
      another: 1,
    };

    expect(stringToString(rec)).toEqual(rec);

    expect(() => stringToString(badRec)).toThrow(ParseError);
  });
});