node_modules/webpack/lib/ErrorHelpers.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

const loaderFlag = "LOADER_EXECUTION";

const webpackOptionsFlag = "WEBPACK_OPTIONS";

exports.cutOffByFlag = (stack, flag) => {
	stack = stack.split("\n");
	for (let i = 0; i < stack.length; i++) {
		if (stack[i].includes(flag)) {
			stack.length = i;
		}
	}
	return stack.join("\n");
};

exports.cutOffLoaderExecution = stack =>
	exports.cutOffByFlag(stack, loaderFlag);

exports.cutOffWebpackOptions = stack =>
	exports.cutOffByFlag(stack, webpackOptionsFlag);

exports.cutOffMultilineMessage = (stack, message) => {
	stack = stack.split("\n");
	message = message.split("\n");

	return stack
		.reduce(
			(acc, line, idx) =>
				line.includes(message[idx]) ? acc : acc.concat(line),
			[]
		)
		.join("\n");
};

exports.cutOffMessage = (stack, message) => {
	const nextLine = stack.indexOf("\n");
	if (nextLine === -1) {
		return stack === message ? "" : stack;
	} else {
		const firstLine = stack.substr(0, nextLine);
		return firstLine === message ? stack.substr(nextLine + 1) : stack;
	}
};

exports.cleanUp = (stack, message) => {
	stack = exports.cutOffLoaderExecution(stack);
	stack = exports.cutOffMessage(stack, message);
	return stack;
};

exports.cleanUpWebpackOptions = (stack, message) => {
	stack = exports.cutOffWebpackOptions(stack);
	stack = exports.cutOffMultilineMessage(stack, message);
	return stack;
};