generateRequest.js

"use strict";

const uuid = require("uuid/v4");

/**
 *  Generates a JSON-RPC 1.0 or 2.0 request
 *  @param {String} method Name of method to call
 *  @param {Array|Object} params Array of parameters passed to the method as specified, or an object of parameter names and corresponding value
 *  @param {String|Number|null} [id] Request ID can be a string, number, null for explicit notification or left out for automatic generation
 *  @param {Object} [options]
 *  @param {Number} [options.version=2] JSON-RPC version to use (1 or 2)
 *  @param {Function} [options.generator] Passed the request, and the options object and is expected to return a request ID
 *  @throws {TypeError} If any of the parameters are invalid
 *  @return {Object} A JSON-RPC 1.0 or 2.0 request
 *  @memberOf Utils
 */
const generateRequest = function (method, params, id, options) {
	if (typeof method !== "string") {
		throw new TypeError(method + " must be a string");
	}

	options = options || {};

	const request = {
		method: method,
	};

	// assume that we are doing a 2.0 request unless specified differently
	if (typeof options.version === "undefined" || options.version !== 1) {
		request.jsonrpc = "2.0";
	}

	if (params) {
		// params given, but invalid?
		const type = typeof params;
		if (type !== "string" && type !== "object" && !Array.isArray(params)) {
			throw new TypeError(params + " must be an object, array or omitted");
		}

		request.params = params;
	}

	// if id was left out, generate one (null means explicit notification)
	if (typeof id === "undefined") {
		const generator =
			typeof options.generator === "function"
				? options.generator
				: function () {
						return uuid();
				  };
		request.id = generator(request, options);
	} else {
		request.id = id;
	}

	return request;
};

module.exports = generateRequest;