Implement FrontMatter parsing.

9 files changed, 81 insertions, 26 deletions

diff --git a/README.md b/README.md
index bdb8f13..1522392 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,25 @@ FlatMatter also supports functions, allowing you to build your own data DSL, and
 forward slash `/` character, meaning that the result of the left operation will be passed as the first argument
 of the next function, and so on, to produce an end result.
 
+Additionally, FlatMatter also parses FrontMatter content, meaning that a FlatMatter file like this:
+
+```yaml
+---
+title: "Hello, World!"
+---
+
+Content goes here.
+```
+
+Would result in this data being created:
+
+```json
+{
+    "title": "Hello, World!",
+    "content": "Content goes here."
+}
+```
+
 ## Install
 
 ```shell
diff --git a/package-lock.json b/package-lock.json
index 7bf2cbe..61c0397 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,14 +1,15 @@
 {
   "name": "flatmatter",
-  "version": "1.0.1",
+  "version": "1.1.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "flatmatter",
-      "version": "1.0.1",
+      "version": "1.1.0",
       "license": "MIT",
       "devDependencies": {
+        "@types/node": "^22.10.10",
         "@vitest/coverage-istanbul": "^2.1.8",
         "@vitest/coverage-v8": "^2.1.8",
         "@vitest/ui": "^2.1.8",
@@ -1086,6 +1087,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/node": {
+      "version": "22.10.10",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.10.10.tgz",
+      "integrity": "sha512-X47y/mPNzxviAGY5TcYPtYL8JsY3kAq2n8fMmKoRCxq/c4v4pyGNCzM2R6+M5/umG4ZfHuT+sgqDYqWc9rJ6ww==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~6.20.0"
+      }
+    },
     "node_modules/@vitest/coverage-istanbul": {
       "version": "2.1.8",
       "resolved": "https://registry.npmjs.org/@vitest/coverage-istanbul/-/coverage-istanbul-2.1.8.tgz",
@@ -2715,9 +2726,9 @@
       "license": "Apache-2.0"
     },
     "node_modules/tsup": {
-      "version": "8.3.5",
-      "resolved": "https://registry.npmjs.org/tsup/-/tsup-8.3.5.tgz",
-      "integrity": "sha512-Tunf6r6m6tnZsG9GYWndg0z8dEV7fD733VBFzFJ5Vcm1FtlXB8xBD/rtrBi2a3YKEV7hHtxiZtW5EAVADoe1pA==",
+      "version": "8.3.6",
+      "resolved": "https://registry.npmjs.org/tsup/-/tsup-8.3.6.tgz",
+      "integrity": "sha512-XkVtlDV/58S9Ye0JxUUTcrQk4S+EqlOHKzg6Roa62rdjL1nGWNUstG0xgI4vanHdfIpjP448J8vlN0oK6XOJ5g==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
@@ -2780,6 +2791,13 @@
         "node": ">=14.17"
       }
     },
+    "node_modules/undici-types": {
+      "version": "6.20.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-6.20.0.tgz",
+      "integrity": "sha512-Ny6QZ2Nju20vw1SRHe3d9jVu6gJ+4e3+MMpqu7pqE5HT6WsTSlce++GQmK5UXS8mzV8DSYHrQH+Xrf2jVcuKNg==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/update-browserslist-db": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/update-browserslist-db/-/update-browserslist-db-1.1.2.tgz",
diff --git a/package.json b/package.json
index 0dd0a5a..1e1ebfb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "flatmatter",
-  "version": "1.0.1",
+  "version": "1.1.0",
   "description": "A data serialization language, and library, with support for functions.",
   "author": "Asko Nõmm <asko@nmm.ee> (https://nmm.ee)",
   "main": "dist/index.js",
@@ -32,6 +32,7 @@
     "@vitest/ui": "^2.1.8",
     "tsup": "^8.3.5",
     "typescript": "^5.7.3",
+    "@types/node": "^22.10.10",
     "vite": "^5.4.11",
     "vitest": "^2.1.8"
   }
diff --git a/src/flatmatter.test.ts b/src/flatmatter.test.ts
index 4c349aa..bbe26d9 100644
--- a/src/flatmatter.test.ts
+++ b/src/flatmatter.test.ts
@@ -1,16 +1,22 @@
-import FlatMatter from "./flatmatter";
+import FlatMatter from "./flatmatter.ts";
 import {assert} from "vitest";
+import ToObject from "./serializers/to_object.ts";
 
 test('Line has no value separator', () => {
-    expect(() => new FlatMatter('test'))
-        .toThrowError("Line on index 0 doesn't have a value separator.");
+    assert.throws(() => new FlatMatter('test'), "Line on index 0 doesn't have a value separator.");
 })
 
 test('Line can only have one value separator', () => {
-    expect(() => new FlatMatter('test: this: that'))
-        .toThrowError("Line on index 0 has multiple value separators.")
+    assert.throws(() => new FlatMatter('test: this: that'), 'Line on index 0 has multiple value separators.')
 })
 
 test('String values can have colon characters', () => {
     assert.doesNotThrow(() => new FlatMatter('test: "this : that"'), Error)
+})
+
+test('FrontMatter creates a new content entry', () => {
+    const fm = new FlatMatter(`---\nthis: true\n---\n\nMarkdown goes here.\n\nAnd here.`);
+    const result = fm.serialize(new ToObject());
+
+    assert.deepEqual(result, {"this": true, "content": "Markdown goes here.\n\nAnd here."});
 })
\ No newline at end of file
diff --git a/src/flatmatter.ts b/src/flatmatter.ts
index 3bf8704..8ffee6f 100644
--- a/src/flatmatter.ts
+++ b/src/flatmatter.ts
@@ -1,9 +1,6 @@
+import { EOL } from "node:os";
 import {trimChar} from "./utils.ts";
 
-export type Matter = {
-    [key: string]: Matter | unknown;
-};
-
 export type ParsedValue = {
     value: unknown;
     computeActions: ComputeAction[];
@@ -15,7 +12,7 @@ export type ComputeAction = {
 };
 
 export interface Serializer {
-    serialize(parsedConfig: Matter): unknown;
+    serialize(parsedConfig: Record<string, unknown>): unknown;
 }
 
 export interface FlatMatterFn {
@@ -26,7 +23,7 @@ export interface FlatMatterFn {
 
 export default class FlatMatter {
     private content: string;
-    private parsedConfig: Matter = {};
+    private parsedConfig: Record<string, unknown> = {};
     private functions: FlatMatterFn[];
 
     constructor(content: string, functions: FlatMatterFn[] = []) {
@@ -37,9 +34,23 @@ export default class FlatMatter {
 
     private parse(): void {
         const lines = this.content.split(/\r?\n/);
+        let frontMatterBreakCount = 0;
 
         for (let i = 0; i < lines.length; i++) {
-            this.parseLine(i, lines[i]);
+            if (lines[i].trim() === "---" && frontMatterBreakCount < 2) {
+                frontMatterBreakCount++;
+                continue;
+            }
+
+
+            // FlatMatter ends, Markdown begins
+            if (frontMatterBreakCount < 2) {
+                this.parseLine(i, lines[i]);
+                continue;
+            }
+
+            this.parsedConfig.content = lines.slice(i).join(EOL).trim();
+            break;
         }
     }
 
@@ -60,7 +71,7 @@ export default class FlatMatter {
 
         const config = keys.reduceRight((acc, key) => {
             return {[key]: acc};
-        }, this.computeValue(parsedValue)) as Matter;
+        }, this.computeValue(parsedValue)) as Record<string, unknown>;
 
         this.parsedConfig = {...this.parsedConfig, ...config};
     }
diff --git a/src/serializers/to_json.test.ts b/src/serializers/to_json.test.ts
index 01f73e0..22f7ba8 100644
--- a/src/serializers/to_json.test.ts
+++ b/src/serializers/to_json.test.ts
@@ -1,5 +1,5 @@
-import FlatMatter from "../flatmatter";
-import ToJson from "./to_json";
+import FlatMatter from "../flatmatter.ts";
+import ToJson from "./to_json.ts";
 
 test("Single-level configuration", () => {
     const fm = new FlatMatter(
diff --git a/src/serializers/to_json.ts b/src/serializers/to_json.ts
index f915a88..76148db 100644
--- a/src/serializers/to_json.ts
+++ b/src/serializers/to_json.ts
@@ -1,7 +1,7 @@
-import type { Matter, Serializer } from "../flatmatter.ts";
+import type { Serializer } from "../flatmatter.ts";
 
 export default class ToJson implements Serializer {
-  serialize(parsedConfig: Matter): string {
+  serialize(parsedConfig: Record<string, unknown>): string {
     return JSON.stringify(parsedConfig);
   }
 }
diff --git a/src/serializers/to_object.ts b/src/serializers/to_object.ts
index 1b07144..a7161cc 100644
--- a/src/serializers/to_object.ts
+++ b/src/serializers/to_object.ts
@@ -1,7 +1,7 @@
-import type { Matter, Serializer } from "../flatmatter.ts";
+import type {Serializer} from "../flatmatter.ts";
 
 export default class ToObject implements Serializer {
-  serialize(parsedConfig: Matter): Matter {
+  serialize(parsedConfig: Record<string, unknown>): Record<string, unknown> {
     return parsedConfig;
   }
 }
diff --git a/tsconfig.json b/tsconfig.json
index f71ca1d..9f40b03 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,7 +8,7 @@
   "compilerOptions": {
     "module": "esnext",
     "target": "esnext",
-    "moduleResolution": "node",
+    "moduleResolution": "nodenext",
     "allowImportingTsExtensions": true,
     "declaration": true,
     "skipLibCheck": true,