boolean-evalation.md

main

Open in playground

export const main = asl.deploy.asStateMachine(async () => {
  const data = {
    num: 42,
    text: "text",
    undefined: undefined,
    null: null,
    timestamp: "2016-03-14T01:59:00Z",
  };

  if (typeof data.num !== "number") {
    throw new ValidationError("num expected to be number");
  }

  if (data.num !== 42) {
    throw new ValidationError("num expected to be 42");
  }

  if (typeof data.text !== "string") {
    throw new ValidationError("text expected to be string");
  }

  if (data.text !== "text") {
    throw new ValidationError("text expected to be 'text'");
  }

  if (data.undefined) {
    throw new ValidationError("undefined expected to be non-truthy'");
  }

  if (data.null) {
    throw new ValidationError("null expected to be non-truthy'");
  }

  if (typeof data.timestamp !== "string") {
    throw new ValidationError("timestamp expected to be string'");
  }
  return "success";
});

class ValidationError extends Error {
  constructor(message: string) {
    super(message);
  }
}

numeric comparison

Open in playground

export const main = asl.deploy.asStateMachine(async () => {
  const condition = 42;
  const items = [2, 42, 3];
  const listWithReturned = items.map((item) => {
    if (item === condition) {
      return { returned: item };
    }
    return {};
  });
  const item = listWithReturned.filter((x) => x.returned);
  return item;
});

class ValidationError extends Error {
  constructor(message: string) {
    super(message);
  }
}