4.1.0 - show error (#3)

* show error
* 4.1.0

index.js

@@ -1,5 +1,3 @@
-"use strict";
-
 const through2 = require("through2"),
       assign = require("object-assign"),
       PluginError = require("plugin-error"),
@@ -39,6 +37,7 @@ module.exports = function (options) {
     if (res.error) {
       res.error.filePath = file.path; 
       res.error.fileContent = (typeof build === "string") ? build : build[res.error.filename]; 
+      printError(res.error);
       return next(new PluginError('gulp-terser', res.error));
     }
 
@@ -51,3 +50,34 @@ module.exports = function (options) {
     return next(null, file);
   });
 };
+
+function alignLine(num, text, longer, maxsize) {
+	let maxlength = process.stdout.columns - 1;
+	num = num + Array(longer - (num + "").length).join(" ");
+	maxlength -= num.length + 3;
+	console.log("\033[36m" + num + " |\033[00m " + text.slice(0, (maxsize < maxlength) ? maxlength : maxsize));
+}
+
+function printError(ev) {
+	if (!ev.fileContent || (ev.line === undefined && ev.col === undefined))
+		return console.error(ev.stack || ev);
+
+	const fileContent = ev.fileContent;
+	const lines = fileContent.replace(/\t/g, "    ").split("\n"),
+		more = (ev.line + " ").length,
+		col = ev.col + 1,
+		pos = (more + 2) + fileContent.split("\n")[ev.line - 1].replace(/[^\t]/g, "").length * 3 + parseInt(col);
+
+	console.log(`\nError with ${ev.plugin} :`);
+	for (let i = ev.line - 5; i < ev.line; i++) {
+		if (lines[i]) {
+			alignLine(i + 1, lines[i], more, pos);
+		}
+	}
+
+	console.log(Array(pos).join(" ") + "\033[91m^\033[00m");
+	console.log("(" + ev.name + ") " + ev.message + " (line : \033[96m" + ev.line + "\033[00m, col : \033[96m" + col + "\033[00m).");
+	console.log(`in : ${ev.filePath}\n`);
+
+	return this.emit('end');
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gulp-terser-js",
-  "version": "4.0.2",
+  "version": "4.1.0",
   "description": "A Terser-js plugin for Gulp",
   "main": "index.js",
   "repository": {