#243 - Refactoring front matter parsing

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 - Updated the activity bar icon for better visibility
 
+### ⚡️ Optimizations
+
+- [#243](https://github.com/estruyf/vscode-front-matter/issues/243): Refactoring front matter parsing
+
 ### 🐞 Fixes
 
 

package.json

@@ -1468,4 +1468,4 @@
   "dependencies": {
     "node-fetch": "^2.6.7"
   }
-}
+}

src/commands/Article.ts

@@ -4,7 +4,6 @@ import * as vscode from 'vscode';
 import { Field, TaxonomyType } from "../models";
 import { format } from "date-fns";
 import { ArticleHelper, Settings, SlugHelper } from '../helpers';
-import matter = require('gray-matter');
 import { Notifications } from '../helpers/Notifications';
 import { extname, basename, parse, dirname } from 'path';
 import { COMMAND_NAME, DefaultFields } from '../constants';
@@ -13,6 +12,7 @@ import { ExplorerView } from '../explorerView/ExplorerView';
 import { DateHelper } from '../helpers/DateHelper';
 import { parseWinPath } from '../helpers/parseWinPath';
 import { Telemetry } from '../helpers/Telemetry';
+import { ParsedFrontMatter } from '../parsers';
 
 
 export class Article {
@@ -103,7 +103,7 @@ export class Article {
    * Update the date in the front matter
    * @param article 
    */
-  public static updateDate(article: matter.GrayMatterFile<string>, forceCreate: boolean = false) {
+  public static updateDate(article: ParsedFrontMatter, forceCreate: boolean = false) {
     article.data = ArticleHelper.updateDates(article.data);   
     return article;
   }
@@ -125,7 +125,7 @@ export class Article {
 
     ArticleHelper.update(
       editor,
-      updatedArticle as matter.GrayMatterFile<string>
+      updatedArticle as ParsedFrontMatter
     );
   }
 
@@ -145,7 +145,7 @@ export class Article {
 
   private static setLastModifiedDateInner(
     document: vscode.TextDocument
-  ): matter.GrayMatterFile<string> | undefined {
+  ): ParsedFrontMatter | undefined {
     const article = ArticleHelper.getFrontMatterFromDocument(document);
 
     if (!article) {
@@ -343,7 +343,7 @@ export class Article {
   /**
    * Get the current article
    */
-  private static getCurrent(): matter.GrayMatterFile<string> | undefined {
+  private static getCurrent(): ParsedFrontMatter | undefined {
     const editor = vscode.window.activeTextEditor;
     if (!editor) {
       return;
@@ -364,7 +364,7 @@ export class Article {
    * @param field 
    * @param forceCreate 
    */
-  private static articleDate(article: matter.GrayMatterFile<string>, field: string, forceCreate: boolean) {
+  private static articleDate(article: ParsedFrontMatter, field: string, forceCreate: boolean) {
     if (typeof article.data[field] !== "undefined" || forceCreate) {
       article.data[field] = Article.formatDate(new Date());
     }

src/commands/Settings.ts

@@ -1,10 +1,9 @@
 import * as vscode from 'vscode';
-import * as matter from 'gray-matter';
 import * as fs from 'fs';
 import { TaxonomyType } from "../models";
 import { SETTING_TAXONOMY_TAGS, SETTING_TAXONOMY_CATEGORIES, EXTENSION_NAME } from '../constants';
 import { ArticleHelper, Settings as SettingsHelper, FilesHelper } from '../helpers';
-import { TomlEngine, getFmLanguage, getFormatOpts } from '../helpers/TomlEngine';
+import { FrontMatterParser } from '../parsers';
 import { DumpOptions } from 'js-yaml';
 import { Notifications } from '../helpers/Notifications';
 
@@ -90,10 +89,6 @@ export class Settings {
       const progressNr = allMdFiles.length/100;
       progress.report({ increment: 0});
 
-      // Get language options
-      const language = getFmLanguage();
-      const langOpts = getFormatOpts(language);
-
       let i = 0;
       for (const file of allMdFiles) {
         progress.report({ increment: (++i/progressNr) });
@@ -102,10 +97,7 @@ export class Settings {
           const txtData = mdFile.getText();
           if (txtData) {
             try {
-              const article = matter(txtData, {
-                ...TomlEngine,
-                ...langOpts
-              });
+              const article = FrontMatterParser.fromFile(txtData);
               if (article && article.data) {
                 const { data } = article;
                 const mdTags = data["tags"];
@@ -218,13 +210,8 @@ export class Settings {
         progress.report({ increment: (++i/progressNr) });
         const mdFile = fs.readFileSync(file.path, { encoding: "utf8" });
         if (mdFile) {
-          const language = getFmLanguage();
-          const langOpts = getFormatOpts(language);
           try {
-            const article = matter(mdFile, {
-              ...TomlEngine,
-              ...langOpts
-            });
+            const article = FrontMatterParser.fromFile(mdFile);
             if (article && article.data) {
               const { data } = article;
               let taxonomies: string[] = data[matterProp];
@@ -239,9 +226,7 @@ export class Settings {
                   data[matterProp] = [...new Set(taxonomies)].sort();
                   const spaces = vscode.window.activeTextEditor?.options?.tabSize;
                   // Update the file
-                  fs.writeFileSync(file.path, matter.stringify(article.content, article.data, {
-                    ...TomlEngine,
-                    ...langOpts,
+                  fs.writeFileSync(file.path, FrontMatterParser.toFile(article.content, article.data, {
                     indent: spaces || 2
                   } as DumpOptions as any), { encoding: "utf8" });
                 }

src/helpers/ArticleHelper.ts

@@ -1,11 +1,10 @@
 import { MarkdownFoldingProvider } from './../providers/MarkdownFoldingProvider';
 import { DEFAULT_CONTENT_TYPE, DEFAULT_CONTENT_TYPE_NAME } from './../constants/ContentType';
 import * as vscode from 'vscode';
-import * as matter from "gray-matter";
 import * as fs from "fs";
 import { DefaultFields, SETTINGS_CONTENT_DEFAULT_FILETYPE, SETTINGS_CONTENT_PLACEHOLDERS, SETTINGS_CONTENT_SUPPORTED_FILETYPES, SETTING_COMMA_SEPARATED_FIELDS, SETTING_DATE_FIELD, SETTING_DATE_FORMAT, SETTING_INDENT_ARRAY, SETTING_REMOVE_QUOTES, SETTING_TAXONOMY_CONTENT_TYPES, SETTING_TEMPLATES_PREFIX } from '../constants';
 import { DumpOptions } from 'js-yaml';
-import { TomlEngine, getFmLanguage, getFormatOpts } from './TomlEngine';
+import { FrontMatterParser, ParsedFrontMatter } from '../parsers';
 import { Extension, Logger, Settings, SlugHelper } from '.';
 import { format, parse } from 'date-fns';
 import { Notifications } from './Notifications';
@@ -56,7 +55,7 @@ export class ArticleHelper {
    * @param editor 
    * @param article 
    */
-  public static async update(editor: vscode.TextEditor, article: matter.GrayMatterFile<string>) {
+  public static async update(editor: vscode.TextEditor, article: ParsedFrontMatter) {
     const update = this.generateUpdate(editor.document, article);
 
     await editor.edit(builder => builder.replace(update.range, update.newText));
@@ -66,7 +65,7 @@ export class ArticleHelper {
    * Generate the update to be applied to the article.
    * @param article 
    */
-  public static generateUpdate(document: vscode.TextDocument, article: matter.GrayMatterFile<string>): vscode.TextEdit {
+  public static generateUpdate(document: vscode.TextDocument, article: ParsedFrontMatter): vscode.TextEdit {
     const nrOfLines = document.lineCount as number;
     const range = new vscode.Range(new vscode.Position(0, 0), new vscode.Position(nrOfLines, 0));
     const removeQuotes = Settings.get(SETTING_REMOVE_QUOTES) as string[];
@@ -117,9 +116,6 @@ export class ArticleHelper {
     const indentArray = Settings.get(SETTING_INDENT_ARRAY) as boolean;
     const commaSeparated = Settings.get<string[]>(SETTING_COMMA_SEPARATED_FIELDS);
 
-    const language = getFmLanguage();
-    const langOpts = getFormatOpts(language);
-
     const spaces = vscode.window.activeTextEditor?.options?.tabSize;
 
     if (commaSeparated) {
@@ -130,9 +126,7 @@ export class ArticleHelper {
       }
     }
     
-    return matter.stringify(content, data, ({
-      ...TomlEngine,
-      ...langOpts,
+    return FrontMatterParser.toFile(content, data, ({
       noArrayIndent: !indentArray,
       skipInvalid: true,
       noCompatMode: true,
@@ -169,7 +163,7 @@ export class ArticleHelper {
   /**
    * Get date from front matter
    */ 
-  public static getDate(article: matter.GrayMatterFile<string> | null) {
+  public static getDate(article: ParsedFrontMatter | null) {
     if (!article) {
       return;
     }
@@ -358,17 +352,12 @@ export class ArticleHelper {
    * @param fileContents 
    * @returns 
    */
-  private static parseFile(fileContents: string, fileName: string): matter.GrayMatterFile<string> | null {
+  private static parseFile(fileContents: string, fileName: string): ParsedFrontMatter | null {
     try {
       const commaSeparated = Settings.get<string[]>(SETTING_COMMA_SEPARATED_FIELDS);
       
       if (fileContents) {
-        const language: string = getFmLanguage(); 
-        const langOpts = getFormatOpts(language);
-        let article: matter.GrayMatterFile<string> | null = matter(fileContents, {
-          ...TomlEngine,
-          ...langOpts
-        });
+        let article = FrontMatterParser.fromFile(fileContents);
   
         if (article?.data) {
           if (commaSeparated) {

src/helpers/CustomScript.ts

@@ -3,13 +3,13 @@ import { window, env as vscodeEnv, ProgressLocation } from 'vscode';
 import { ArticleHelper } from '.';
 import { Folders } from '../commands/Folders';
 import { exec } from 'child_process';
-import matter = require('gray-matter');
 import * as os from 'os';
 import { join } from 'path';
 import { Notifications } from './Notifications';
 import ContentProvider from '../providers/ContentProvider';
 import { Dashboard } from '../commands/Dashboard';
 import { DashboardCommand } from '../dashboardWebView/DashboardCommand';
+import { ParsedFrontMatter } from '../parsers';
 
 export class CustomScript {
 
@@ -117,7 +117,7 @@ export class CustomScript {
     });
   }
 
-  private static async runScript(wsPath: string, article: matter.GrayMatterFile<string> | null, contentPath: string, script: ICustomScript): Promise<string | null> {
+  private static async runScript(wsPath: string, article: ParsedFrontMatter | null, contentPath: string, script: ICustomScript): Promise<string | null> {
     return new Promise((resolve, reject) => {
       let articleData = "";
       if (os.type() === "Windows_NT") {

src/helpers/SeoHelper.ts

@@ -1,10 +1,10 @@
 import * as vscode from 'vscode';
 import { ArticleHelper } from '.';
-import matter = require('gray-matter');
+import { ParsedFrontMatter } from '../parsers';
 
 export class SeoHelper {
 
-  public static checkLength(editor: vscode.TextEditor, collection: vscode.DiagnosticCollection, article: matter.GrayMatterFile<string>, fieldName: string, length: number) {
+  public static checkLength(editor: vscode.TextEditor, collection: vscode.DiagnosticCollection, article: ParsedFrontMatter, fieldName: string, length: number) {
     const value = article.data[fieldName];
     if (value.length > length) {
       const text = editor.document.getText();

src/helpers/TomlEngine.ts

@@ -1,31 +0,0 @@
-import * as toml from '@iarna/toml';
-import { SETTING_FRONTMATTER_TYPE } from '../constants';
-import { Settings } from './SettingsHelper';
-
-export const getFmLanguage = (): string => {
-  const language = Settings.get(SETTING_FRONTMATTER_TYPE) as string || "YAML";
-  return language.toLowerCase();
-};
-
-export const getFormatOpts = (format: string): { language: string, delimiters: string | [string, string] | undefined } => {
-  const formats: { [prop: string]: { language: string, delimiters: string | [string, string] | undefined }} = {
-    yaml: { language: 'yaml', delimiters: '---' },
-    toml: { language: 'toml', delimiters: '+++' },
-    json: { language: 'json', delimiters: '---' },
-  };
-
-  return formats[format];
-};
-
-export const TomlEngine = {
-  engines: {
-    toml: {
-      parse: (value: string) => {
-        return toml.parse(value);
-      },
-      stringify: (value: any) => {
-        return toml.stringify(value);
-      }
-    }
-  }
-};

src/helpers/index.ts

@@ -9,6 +9,7 @@ export * from './FrameworkDetector';
 export * from './GroupBy';
 export * from './ImageHelper';
 export * from './Logger';
+export * from './MediaHelpers';
 export * from './MediaLibrary';
 export * from './MessageHelper';
 export * from './Notifications';
@@ -19,7 +20,7 @@ export * from './SettingsHelper';
 export * from './SlugHelper';
 export * from './Sorting';
 export * from './StringHelpers';
-export * from './TomlEngine';
+export * from './Telemetry';
 export * from './decodeBase64Image';
 export * from './getNonce';
 export * from './isValidFile';

src/parsers/FrontMatterParser.ts

@@ -0,0 +1,51 @@
+import { Engines, getFormatOpts } from ".";
+import * as matter from "gray-matter";
+import { Settings } from "../helpers";
+import { SETTING_FRONTMATTER_TYPE } from "../constants";
+
+export interface Format {
+  language: string;
+  delimiters: string | [string, string] | undefined;
+}
+
+export interface ParsedFrontMatter {
+  data: { [key: string]: any };
+  content: string
+}
+
+export class FrontMatterParser {
+
+  public static fromFile(content: string): ParsedFrontMatter {
+    const format = getFormatOpts(this.getLanguage());
+    const result = matter(content, { ...Engines, ...format });
+    // in the absent of a body when serializing an entry we use an empty one
+    // when calling `toFile`, so we don't want to add it when parsing.
+
+    return {
+      data: { ...result.data },
+      content: (result.content.trim() && result.content)
+    };
+  }
+
+  public static toFile(
+    content: string,
+    metadata: Object,
+    options?: any
+  ) {
+    // Stringify to YAML if the format was not set
+    const format = getFormatOpts(this.getLanguage());
+
+    const trimLastLineBreak = content.slice(-1) !== '\n';
+    const file = matter.stringify(content, metadata, {
+      ...Engines,
+      ...options,
+      ...format
+    });
+    return trimLastLineBreak && file.slice(-1) === '\n' ? file.substring(0, file.length - 1) : file;
+  }
+
+  private static getLanguage() {
+    const language = Settings.get(SETTING_FRONTMATTER_TYPE) as string || "YAML";
+    return language.toLowerCase();
+  }
+}

src/parsers/ParserEngines.ts

@@ -0,0 +1,25 @@
+import * as toml from '@iarna/toml';
+import { Format } from '.';
+
+export const getFormatOpts = (format: string): Format => {
+  const formats: { [prop: string]: Format} = {
+    yaml: { language: 'yaml', delimiters: '---' },
+    toml: { language: 'toml', delimiters: '+++' },
+    json: { language: 'json', delimiters: '---' },
+  };
+
+  return formats[format];
+};
+
+export const Engines = {
+  engines: {
+    toml: {
+      parse: (value: string) => {
+        return toml.parse(value);
+      },
+      stringify: (value: any) => {
+        return toml.stringify(value);
+      }
+    }
+  }
+}

src/parsers/index.ts

@@ -0,0 +1,2 @@
+export * from './FrontMatterParser';
+export * from './ParserEngines';