Refactor code to comply with ESLint rules

Major refactoring using ESLint with rules from AirBnb and Vue.

Enable most of the ESLint rules and do necessary linting in the code.
Also add more information for rules that are disabled to describe what
they are and why they are disabled.

Allow logging (`console.log`) in test files, and in development mode
(e.g. when working with `npm run serve`), but disable it when
environment is production (as pre-configured by Vue). Also add flag
(`--mode production`) in `lint:eslint` command so production linting is
executed earlier in lifecycle.

Disable rules that requires a separate work. Such as ESLint rules that
are broken in TypeScript: no-useless-constructor (eslint/eslint#14118)
and no-shadow (eslint/eslint#13014).

src/application/Parser/DocumentationParser.ts

@@ -1,61 +1,64 @@
 import { DocumentableData, DocumentationUrlsData } from 'js-yaml-loader!@/*';
 
 export function parseDocUrls(documentable: DocumentableData): ReadonlyArray<string> {
-    if (!documentable) {
-        throw new Error('documentable is null or undefined');
-    }
-    const docs = documentable.docs;
-    if (!docs || !docs.length) {
-        return [];
-    }
-    let result = new DocumentationUrlContainer();
-    result = addDocs(docs, result);
-    return result.getAll();
+  if (!documentable) {
+    throw new Error('documentable is null or undefined');
+  }
+  const { docs } = documentable;
+  if (!docs || !docs.length) {
+    return [];
+  }
+  let result = new DocumentationUrlContainer();
+  result = addDocs(docs, result);
+  return result.getAll();
 }
 
-function addDocs(docs: DocumentationUrlsData, urls: DocumentationUrlContainer): DocumentationUrlContainer {
-    if (docs instanceof Array) {
-        urls.addUrls(docs);
-    } else if (typeof docs === 'string') {
-        urls.addUrl(docs);
-    } else {
-        throw new Error('Docs field (documentation url) must a string or array of strings');
-    }
-    return urls;
+function addDocs(
+  docs: DocumentationUrlsData,
+  urls: DocumentationUrlContainer,
+): DocumentationUrlContainer {
+  if (docs instanceof Array) {
+    urls.addUrls(docs);
+  } else if (typeof docs === 'string') {
+    urls.addUrl(docs);
+  } else {
+    throw new Error('Docs field (documentation url) must a string or array of strings');
+  }
+  return urls;
 }
 
 class DocumentationUrlContainer {
-    private readonly urls = new Array<string>();
+  private readonly urls = new Array<string>();
 
-    public addUrl(url: string) {
-        validateUrl(url);
-        this.urls.push(url);
-    }
+  public addUrl(url: string) {
+    validateUrl(url);
+    this.urls.push(url);
+  }
 
-    public addUrls(urls: readonly any[]) {
-        for (const url of urls) {
-            if (typeof url !== 'string') {
-                throw new Error('Docs field (documentation url) must be an array of strings');
-            }
-            this.addUrl(url);
-        }
+  public addUrls(urls: readonly string[]) {
+    for (const url of urls) {
+      if (typeof url !== 'string') {
+        throw new Error('Docs field (documentation url) must be an array of strings');
+      }
+      this.addUrl(url);
     }
+  }
 
-    public getAll(): ReadonlyArray<string> {
-        return this.urls;
-    }
+  public getAll(): ReadonlyArray<string> {
+    return this.urls;
+  }
 }
 
 function validateUrl(docUrl: string): void {
-    if (!docUrl) {
-        throw new Error('Documentation url is null or empty');
-    }
-    if (docUrl.includes('\n')) {
-        throw new Error('Documentation url cannot be multi-lined.');
-    }
-    const res = docUrl.match(
-        /(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)/g);
-    if (res == null) {
-        throw new Error(`Invalid documentation url: ${docUrl}`);
-    }
+  if (!docUrl) {
+    throw new Error('Documentation url is null or empty');
+  }
+  if (docUrl.includes('\n')) {
+    throw new Error('Documentation url cannot be multi-lined.');
+  }
+  const validUrlRegex = /(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_+.~#?&//=]*)/g;
+  const res = docUrl.match(validUrlRegex);
+  if (res == null) {
+    throw new Error(`Invalid documentation url: ${docUrl}`);
+  }
 }