typed-utilities/build/__tests__/Result.test.js

Strongly typed general purpose utilities

"use strict";

var _ = require("..");

describe(`Result`, () => {
  test(`Sync`, () => {
    const divide = (a, b) => {
      if (b === 0) {
        throw new Error(`division by zero`);
      }

      return a / b;
    };

    const res1 = _.Result.tryCatch(() => divide(1, 10));

    const res2 = _.Result.tryCatch(() => divide(1, 0));

    expect(_.Result.is.ok(res1)).toEqual(true);
    expect(_.Result.is.err(res1)).toEqual(false);
    expect(_.Result.to.okValue(res1)).toEqual(0.1);
    expect(_.Result.is.ok(res2)).toEqual(false);
    expect(_.Result.is.err(res2)).toEqual(true);
    expect(_.Result.to.errError(res2)).toBeInstanceOf(Error);
    const t1 = [1, 2, 3].map(_.Result.of.ok);

    for (const m of t1) {
      expect(_.Result.is.ok(m)).toEqual(true);
    }

    const isNotOdd = new Error(`not odd`);

    const keepOdd = v => v % 2 === 1 ? _.Result.of.ok(v) : _.Result.of.err(isNotOdd);

    const t2 = t1.map(r => _.Result.match(r, {
      ok: keepOdd,
      err: error => _.Result.of.err(error)
    }));
    expect(t2).toEqual([_.Result.of.ok(1), _.Result.of.err(isNotOdd), _.Result.of.ok(3)]);
    expect(t2.filter(_.Result.is.ok).map(_.Result.to.okValue)).toEqual([1, 3]);
  });
  test(`Async`, async () => {
    const divide = async (a, b) => {
      await (0, _.sleep)(1);

      if (b === 0) {
        throw new Error(`division by zero`);
      }

      return a / b;
    };

    const res1 = await _.Result.tryCatchAsync(async () => await divide(1, 10));
    const res2 = await _.Result.tryCatchAsync(async () => await divide(1, 0));
    expect(_.Result.is.ok(res1)).toEqual(true);
    expect(_.Result.is.err(res1)).toEqual(false);
    expect(_.Result.to.okValue(res1)).toEqual(0.1);
    expect(_.Result.is.ok(res2)).toEqual(false);
    expect(_.Result.is.err(res2)).toEqual(true);
    expect(_.Result.to.errError(res2)).toBeInstanceOf(Error);
    const t1 = [1, 2, 3].map(_.Result.of.ok);

    for (const m of t1) {
      expect(_.Result.is.ok(m)).toEqual(true);
    }

    const isNotOdd = new Error(`not odd`);

    const keepOdd = v => v % 2 === 1 ? _.Result.of.ok(v) : _.Result.of.err(isNotOdd);

    const t2 = t1.map(r => _.Result.match(r, {
      ok: keepOdd,
      err: error => _.Result.of.err(error)
    }));
    expect(t2).toEqual([_.Result.of.ok(1), _.Result.of.err(isNotOdd), _.Result.of.ok(3)]);
    expect(t2.filter(_.Result.is.ok).map(_.Result.to.okValue)).toEqual([1, 3]);
  });
});
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