Add some doc/comments

Author: geowarin

src/extractError.js renamed to src/core/extractWebpackError.js

@@ -1,6 +1,13 @@
 const RequestShortener = require("webpack/lib/RequestShortener");
+
+// TODO: allow the location to be customized in options
 const requestShortener = new RequestShortener(process.cwd());
 
+/*
+ This logic is mostly duplicated from webpack/lib/Stats.js#toJson()
+ See: https://github.com/webpack/webpack/blob/2f618e733aab4755deb42e9d8e859609005607c0/lib/Stats.js#L89
+*/
+
 function extractError (e) {
   return {
     message: e.message,

src/formatErrors.js renamed to src/core/formatErrors.js

@@ -1,3 +1,6 @@
+/**
+ * Applies formatters to all AnnotatedErrors.
+ */
 function formatErrors(errors, formatters, errorType) {
   const format = (formatter) => formatter(errors, errorType) || [];
   const flatten = (accum, curr) => accum.concat(curr);

src/core/transformErrors.js

@@ -0,0 +1,30 @@
+const extractError = require('./extractWebpackError');
+
+/**
+ * Applies all transformers to all errors and returns "annotated"
+ * errors.
+ *
+ * Each transformer should have the following signature WebpackError => AnnotatedError
+ *
+ * A WebpackError has the following fields:
+ * - message
+ * - file
+ * - origin
+ * - name
+ * - severity
+ * - webpackError (original error)
+ *
+ * An AnnotatedError should be an extension (Object.assign) of the WebpackError
+ * and add whatever information is convenient for formatter.
+ * In particular, they should have a 'type' field and a 'priority' field.
+ *
+ * The plugin will only display errors having maximum priority at the same time.
+ */
+function processErrors (errors, transformers) {
+  const transform = (error, transformer) => transformer(error);
+  const applyTransformations = (error) => transformers.reduce(transform, error);
+
+  return errors.map(extractError).map(applyTransformations);
+}
+
+module.exports = processErrors;

src/formatters/defaultError.js

@@ -9,7 +9,7 @@ function displayError(index, severity, { file, message, origin }) {
     message,
     (origin ? origin : undefined),
     ''
-  ].filter((chunk) => chunk !== undefined);
+  ].filter(chunk => chunk !== undefined);
 }
 
 function isDefaultError(error) {

src/friendly-errors-plugin.js

@@ -1,8 +1,8 @@
 const path = require('path');
 const chalk = require('chalk');
 const os = require('os');
-const processErrors = require('./processError');
-const formatErrors = require('./formatErrors');
+const transformErrors = require('./core/transformErrors');
+const formatErrors = require('./core/formatErrors');
 const debug = require('./debug');
 
 const transformers = [
@@ -51,25 +51,30 @@ class FriendlyErrorsWebpackPlugin {
       if (!hasErrors && !hasWarnings) {
         const time = stats.endTime - stats.startTime;
         debug.log(chalk.green('Compiled successfully in ' + time + 'ms'));
+
         if (this.compilationSuccessMessage) {
           debug.log(this.compilationSuccessMessage);
         }
+
       } else if (hasErrors) {
+
         const { errors } = stats.compilation;
-        const processedErrors = processErrors(errors, transformers);
+        const processedErrors = transformErrors(errors, transformers);
         const nbErrors = processedErrors.length;
         displayCompilationMessage(`Failed to compile with ${nbErrors} errors`, 'red');
 
         if (this.notifier) {
           this.notify('Error', processedErrors[0]);
         }
 
-        const topErrors = getMaxSeverityErrors(processedErrors, 'severity');
+        const topErrors = getMaxSeverityErrors(processedErrors);
         formatErrors(topErrors, formatters, 'Error')
           .forEach((chunk) => debug.log(chunk));
+
       } else if (hasWarnings) {
+
         const { warnings } = stats.compilation;
-        const processedWarns = processErrors(warnings, transformers);
+        const processedWarns = transformErrors(warnings, transformers);
         const nbWarning = processedWarns.length;
         displayCompilationMessage(`Compiled with ${nbWarning} warnings`, 'yellow');
 
@@ -98,20 +103,6 @@ function getMaxInt(collection, propertyName) {
 
 module.exports = FriendlyErrorsWebpackPlugin;
 
-function displayError (index, severity, error) {
-  if (error.file) {
-    debug.log(chalk.red((index + 1) + ') ' + severity) + ' in ' + error.file);
-  } else {
-    debug.log(chalk.red((index + 1) + ') ' + severity));
-  }
-  debug.log();
-  debug.log(error.message);
-  if (error.origin) {
-    debug.log(error.origin);
-  }
-  debug.log();
-}
-
 function displayCompilationMessage (message, color) {
   debug.log();
   debug.log(chalk[color](message));

src/processError.js

@@ -1,4 +1,4 @@
-const formatErrors = require('../../src/formatErrors');
+const formatErrors = require('../../src/core/formatErrors');
 const expect = require('expect');
 const test = require('ava');
 
@@ -11,7 +11,7 @@ const allCaps = (errors) => errors
 const notFound = (errors) => errors
   .filter(({ type }) => type === 'not-found').map(() => 'Not found');
 
-const formatters = [allCaps]
+const formatters = [allCaps];
 
 test('formats the error based on the matching formatters', () => {
   const errors = [