counterfact/dist/server/tools.js

Generate a TypeScript-based mock server from an OpenAPI spec in seconds — with stateful routes, hot reload, and REPL support.

import { generate } from "json-schema-faker";
/**
 * A collection of utility helpers made available to route handlers via
 * `$.tools`.
 *
 * Provides random selection, content-type acceptance checking, and
 * schema-based random data generation.
 */
export class Tools {
    headers;
    constructor({ headers = {}, } = {}) {
        this.headers = headers;
    }
    /**
     * Returns a randomly selected element from `array`.
     *
     * @param array - The array to pick from.
     * @returns A random element.
     */
    oneOf(array) {
        return array[Math.floor(Math.random() * array.length)];
    }
    /**
     * Returns `true` when the request's `Accept` header is compatible with
     * `contentType`.
     *
     * A missing or empty `Accept` header is treated as `*/*` (accepts anything).
     *
     * @param contentType - The MIME type to check (e.g. `"application/json"`).
     */
    accepts(contentType) {
        const acceptHeader = Object.entries(this.headers).find(([key]) => key.toLowerCase() === "accept")?.[1];
        if (acceptHeader === "" || acceptHeader === undefined) {
            return true;
        }
        const acceptTypes = String(acceptHeader).split(",");
        return acceptTypes.some((acceptType) => {
            const [type, subtype] = acceptType.trim().split("/");
            return ((type === "*" || type === contentType.split("/")[0]) &&
                (subtype === "*" || subtype === contentType.split("/")[1]));
        });
    }
    /**
     * Generates a random value that satisfies `schema` using json-schema-faker.
     *
     * @param schema - A JSON Schema object.
     * @returns A promise that resolves to a generated value.
     */
    randomFromSchema(schema) {
        return generate(schema, { useExamplesValue: true, fillProperties: false });
    }
}