add unit test for utils/format-output.js

Author: Elrey Belmonti

test/utils/format-assets.spec.js

@@ -1,7 +1,5 @@
 "use strict";
 
-const { expect } = require("chai");
-
 const { _getAssetSize, _getTotalSize, _printAssets } = require("../../utils/format-assets");
 
 describe("format-assets.js", () => {

test/utils/format-output.spec.js

@@ -0,0 +1,38 @@
+"use strict";
+
+const { _isLikelyASyntaxError, _lineJoin, _formatMessage } = require("../../utils/format-output");
+
+describe("format-output.js", () => {
+  describe("#_isLikelyASyntaxError", () => {
+    context("when message is a syntax error", () => {
+      it("returns true", () => {
+        const message = "Syntax error: missing ; before statement";
+        expect(_isLikelyASyntaxError(message)).to.be.true;
+      });
+    });
+
+    context("when message is a type error", () => {
+      it("returns false", () => {
+        const message = "Type error: null has no properties";
+        expect(_isLikelyASyntaxError(message)).to.be.false;
+      });
+    });
+  });
+
+  describe("#_formatMessage", () => {
+    const message1 = "Module build failed: SyntaxError: missing ; before statement";
+    const message2 = "/Module not found: Error: Cannot resolve 'file' or 'directory'/";
+    it("returns a readable user friendly message", () => {
+      expect(_formatMessage(message1)).to.equal("Syntax error: missing ; before statement");
+      expect(_formatMessage(message2)).to.equal("/Module not found:/");
+    });
+  });
+
+  describe("#_lineJoin", () => {
+    it("returns the elements of an array on a newline as a string", () => {
+      const array = ["word", "word2", "word3"];
+      const output = "word\nword2\nword3";
+      expect(_lineJoin(array)).to.equal(output);
+    });
+  });
+});

utils/format-output.js

@@ -2,25 +2,19 @@
 
 const friendlySyntaxErrorLabel = "Syntax error:";
 
-function isLikelyASyntaxError(message) {
+function _isLikelyASyntaxError(message) {
   return message.indexOf(friendlySyntaxErrorLabel) !== -1;
 }
 
-function formatMessage(message) {
+function _formatMessage(message) {
   return message
-    .replace(
-      "Module build failed: SyntaxError:",
-      friendlySyntaxErrorLabel
-    )
-    .replace(
-      /Module not found: Error: Cannot resolve 'file' or 'directory'/,
-      "Module not found:"
-    )
+    .replace("Module build failed: SyntaxError:", friendlySyntaxErrorLabel)
+    .replace(/Module not found: Error: Cannot resolve 'file' or 'directory'/, "Module not found:")
     .replace(/^\s*at\s.*:\d+:\d+[\s\)]*\n/gm, "")
     .replace("./~/css-loader!./~/postcss-loader!", "");
 }
 
-function lineJoin(arr) {
+function _lineJoin(arr) {
   return arr.join("\n");
 }
 
@@ -31,20 +25,20 @@ function formatOutput(stats) {
   const hasWarnings = stats.hasWarnings();
 
   const json = stats.toJson();
-  let formattedErrors = json.errors.map(message => `Error in ${formatMessage(message)}`);
-  const formattedWarnings = json.warnings.map(message => `Warning in ${formatMessage(message)}`);
+  let formattedErrors = json.errors.map(message => `Error in ${_formatMessage(message)}`);
+  const formattedWarnings = json.warnings.map(message => `Warning in ${_formatMessage(message)}`);
 
   if (hasErrors) {
     output.push("{red-fg}Failed to compile.{/}");
     output.push("");
-    if (formattedErrors.some(isLikelyASyntaxError)) {
-      formattedErrors = formattedErrors.filter(isLikelyASyntaxError);
+    if (formattedErrors.some(_isLikelyASyntaxError)) {
+      formattedErrors = formattedErrors.filter(_isLikelyASyntaxError);
     }
     formattedErrors.forEach(message => {
       output.push(message);
       output.push("");
     });
-    return lineJoin(output);
+    return _lineJoin(output);
   }
 
   if (hasWarnings) {
@@ -55,13 +49,16 @@ function formatOutput(stats) {
       output.push("");
     });
 
-    return lineJoin(output);
+    return _lineJoin(output);
   }
 
   output.push("{green-fg}Compiled successfully!{/}");
   output.push("");
 
-  return lineJoin(output);
+  return _lineJoin(output);
 }
 
-module.exports = formatOutput;
+module.exports = { formatOutput,
+  _formatMessage,
+  _isLikelyASyntaxError,
+  _lineJoin };