/
Either_test.js
119 lines (103 loc) · 2.09 KB
/
Either_test.js
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import { assertIsEquivalent } from "./asserts.js";
import Either from "./Either.js";
Deno.test(
"Either: #right",
() =>
assertIsEquivalent(Either.right(42), Either.Right(42))
);
Deno.test(
"Either.Right: #alt",
() =>
assertIsEquivalent(
Either.Right(42).alt(Either.Right(24)),
Either.Right(42)
)
);
Deno.test(
"Either.Right: #ap - Composition",
() => {
const containerA = Either.Right(42);
const containerB = Either.Right(x => x + 2);
const containerC = Either.Right(x => x * 2);
assertIsEquivalent(
containerA.ap(containerB.ap(containerC.map(a => b => c => a(b(c))))),
containerA.ap(containerB).ap(containerC)
);
}
);
Deno.test(
"Either.Right: #chain",
() =>
assertIsEquivalent(
Either.Right(42).chain(x => Either.of(x * 2)),
Either.Right(84)
)
);
Deno.test(
"Either.Right: #map",
() =>
assertIsEquivalent(
Either.Right(42).map(x => x * 2),
Either.Right(84)
)
);
Deno.test(
"Either.Right: #map - Identity",
() => {
const container = Either.Right(42);
assertIsEquivalent(
container.map(x => x),
container
);
}
);
Deno.test(
"Either.Right: #map - Composition",
() => {
const container = Either.Right(42);
const f = x => x + 2;
const g = x => x * 2;
assertIsEquivalent(
container.map(f).map(g),
container.map(x => g(f(x)))
);
}
);
Deno.test(
"Either.Left: #alt",
() =>
assertIsEquivalent(
Either.Left(32).alt(Either.Right(42)),
Either.Right(42)
)
);
Deno.test(
"Either.Left: #map",
() =>
assertIsEquivalent(
Either.Left(32).map(x => x * 2),
Either.Left(32)
)
);
Deno.test(
"Either.Left: #map - Identity",
() => {
const container = Either.Left(32);
assertIsEquivalent(
container.map(x => x),
container
);
}
);
Deno.test(
"Either.Left: #map - Composition",
() => {
const container = Either.Left(32);
const f = x => x + 2;
const g = x => x * 2;
assertIsEquivalent(
container.map(f).map(g),
container.map(x => g(f(x)))
);
}
);