mapping-assertions.ts

// The entry file of your WebAssembly module.

class ExpectTo<T> {
  value: T

  constructor(value: T) {
    this.value = value
  }

  equal(other: T): void {
    // use `log.fatal('{} !== {}', [this.value.toString(), other.toString()])` instead
    assert(
      this.value == other,
      this.value.toString() + ' !== ' + other.toString()
    )
  }
}

class Expect<T> {
  value: T

  constructor(value: T) {
    this.value = value
  }

  get to(): ExpectTo<T> {
    return new ExpectTo(this.value)
  }
}

function expect<T>(value: T): Expect<T> {
  return new Expect(value)
}

class Foo {
  value: i32

  constructor(value: i32) {
    this.value = value
  }

  // Required for every type used with `expect`
  toString(): string {
    return 'Foo { value: ' + this.value.toString() + ' }'
  }
}

export function add(a: i32, b: i32): i32 {
  expect(new Foo(a)).to.equal(new Foo(b))
  expect(a).to.equal(b)
  return a + b
}