serwist/src/utils/assert.ts

A Swiss Army knife for service workers.

/*
  Copyright 2018 Google LLC

  Use of this source code is governed by an MIT-style
  license that can be found in the LICENSE file or at
  https://opensource.org/licenses/MIT.
*/

import type { MapLikeObject } from "../types.js";
import { SerwistError } from "./SerwistError.js";

/*
 * This method throws if the supplied value is not an array.
 * The destructed values are required to produce a meaningful error for users.
 * The destructed and restructured object is so it's clear what is
 * needed.
 */
const isArray = (value: any[], details: MapLikeObject) => {
  if (!Array.isArray(value)) {
    throw new SerwistError("not-an-array", details);
  }
};

const hasMethod = (object: MapLikeObject, expectedMethod: string, details: MapLikeObject) => {
  const type = typeof object[expectedMethod];
  if (type !== "function") {
    details.expectedMethod = expectedMethod;
    throw new SerwistError("missing-a-method", details);
  }
};

const isType = (object: unknown, expectedType: string, details: MapLikeObject) => {
  if (typeof object !== expectedType) {
    details.expectedType = expectedType;
    throw new SerwistError("incorrect-type", details);
  }
};

const isInstance = (
  object: unknown,
  // biome-ignore lint/complexity/noBannedTypes: Need the general type to do the check later.
  expectedClass: Function,
  details: MapLikeObject,
) => {
  if (!(object instanceof expectedClass)) {
    details.expectedClassName = expectedClass.name;
    throw new SerwistError("incorrect-class", details);
  }
};

const isOneOf = (value: any, validValues: any[], details: MapLikeObject) => {
  if (!validValues.includes(value)) {
    details.validValueDescription = `Valid values are ${JSON.stringify(validValues)}.`;
    throw new SerwistError("invalid-value", details);
  }
};

const isArrayOfClass = (
  value: any,
  // biome-ignore lint/complexity/noBannedTypes: Need general type to do check later.
  expectedClass: Function,
  details: MapLikeObject,
) => {
  const error = new SerwistError("not-array-of-class", details);
  if (!Array.isArray(value)) {
    throw error;
  }

  for (const item of value) {
    if (!(item instanceof expectedClass)) {
      throw error;
    }
  }
};

const finalAssertExports =
  process.env.NODE_ENV === "production"
    ? null
    : {
        hasMethod,
        isArray,
        isInstance,
        isOneOf,
        isType,
        isArrayOfClass,
      };

export { finalAssertExports as assert };