node-error-chain/src/packages/render/index.js

"use strict";

const chalk = require("chalk");
const syncpipe = require("syncpipe");

const { validateArguments } = require("@validatem/core");
const required = require("@validatem/required");
const defaultTo = require("@validatem/default-to");
const isBoolean = require("@validatem/is-boolean");
const oneOf = require("@validatem/one-of");

const stripErrorFromStack = require("./strip-error-from-stack");
const isInstanceOf = require("./is-instance-of");
const getChain = require("../get-chain");

function prefixExtraLines(string, prefix) {
	return string
		.split("\n")
		.map((line, i) => {
			if (i > 0) {
				return prefix + line;
			} else {
				return line;
			}
		})
		.join("\n");
}

function formattedErrorHeading(error, colorAll = false, indentation) {
	let formattedMessage = syncpipe(error.message, [
		(_) => _.trim(),
		(_) => (indentation != null)
			? prefixExtraLines(_, indentation)
			: _
	]);

	let formattedName = chalk.red(`${chalk.bold(error.name)}:`);

	let coloredMessage = (colorAll === true) ? chalk.red(formattedMessage) : formattedMessage;

	return `${formattedName} ${coloredMessage}`;
}

function formattedError(error, indentation = "", prefix = "") {
	let strippedStack = stripErrorFromStack(error.stack);

	let formattedStack = strippedStack.split("\n").map((line) => {
		if (line.trim().length === 0) {
			return null;
		} else if (line[0] === " ") {
			return indentation + line;
		} else {
			return indentation + `   ${line}`;
		}
	}).filter(line => line != null).join("\n");

	let heading = indentation + prefix + formattedErrorHeading(error);

	return `${heading}\n${formattedStack}`;
}

module.exports = function renderError(_error, _options) {
	let [ error, options ] = validateArguments(arguments, {
		error: [ required, isInstanceOf(Error) ],
		options: [ defaultTo({}), {
			// color: [ oneOf([ true, false, "auto" ]), defaultTo("auto") ], // FIXME: Implement
			allStacktraces: [ isBoolean, defaultTo(false) ]
		}]
	});

	let {allStacktraces} = options;

	let errors = getChain(error);

	if (errors.length === 1) {
		// Special case: there's not actually a cause chain, so we should render the error more simply
		return formattedError(errors[0]);
	} else {
		let detailedErrorsToDisplay = (allStacktraces === true) ? errors : errors.slice(-1);

		let summary = errors.map((error, i) => {
			let prefix = (i > 0) ? "⤷ " : "";

			/* IDEA: After every summarized error, add a summarized stacktrace; that is, a stacktrace that only contains the 'user code' entries that might point the developer at the source of the problem. To do that, we should filter out all node_modules and error-chain stuff, as well as internals like timers.js. Then, we should deduplicate lines across stacktraces, and hide the function name if it's boilerplate (eg. Promise.try.then stuff). Try this out with the 'rpm' regex in the CVM smartctl wrapper, as that covers all bases; duplication, stacktraces without user code, etc. */
			// let cleanStack = error.stack.split("\n").filter((line) => {
			// 	return (!line.includes("node_modules")
			// 		&& !line.includes("node-error-chain")
			// 		&& !line.includes("(timers.js")
			// 		&& !line.includes("<anonymous>")
			// 	);
			// }).join("\n");

			// console.log(cleanStack);
			
			return prefix + formattedErrorHeading(error, false, "  ");
		}).join("\n");

		let stacktraces = detailedErrorsToDisplay.map((error, i) => {
			let causedByPrefix = (i > 0 ? "Caused by: " : "");
			let causedByPadding = (i > 0) ? " " : "";

			return formattedError(error, causedByPadding, causedByPrefix);
		}).join("\n\n");

		let stacktraceSection = (allStacktraces === true)
			? `${chalk.cyan("All stacktraces:")}\n\n${stacktraces}`
			: `${chalk.cyan("Stacktrace for original error:")}\n\n${stacktraces}`;

		return `${summary}\n\n${stacktraceSection}`;
	}
};