Supports white list for function syntax (#77)

* support name list for FN syntax

* use default parameter

Co-authored-by: Johann150 <johann.galle@protonmail.com>

Co-authored-by: Johann150 <johann.galle@protonmail.com>

etc/mfm-js.api.md

@@ -231,7 +231,9 @@ export const N_URL: (value: string, brackets?: boolean | undefined) => NodeType<
 export type NodeType<T extends MfmNode['type']> = T extends 'quote' ? MfmQuote : T extends 'search' ? MfmSearch : T extends 'blockCode' ? MfmCodeBlock : T extends 'mathBlock' ? MfmMathBlock : T extends 'center' ? MfmCenter : T extends 'unicodeEmoji' ? MfmUnicodeEmoji : T extends 'emojiCode' ? MfmEmojiCode : T extends 'bold' ? MfmBold : T extends 'small' ? MfmSmall : T extends 'italic' ? MfmItalic : T extends 'strike' ? MfmStrike : T extends 'inlineCode' ? MfmInlineCode : T extends 'mathInline' ? MfmMathInline : T extends 'mention' ? MfmMention : T extends 'hashtag' ? MfmHashtag : T extends 'url' ? MfmUrl : T extends 'link' ? MfmLink : T extends 'fn' ? MfmFn : T extends 'text' ? MfmText : never;
 
 // @public (undocumented)
-export function parse(input: string): MfmNode[];
+export function parse(input: string, opts?: Partial<{
+    fnNameList: string[];
+}>): MfmNode[];
 
 // Warning: (ae-forgotten-export) The symbol "MfmPlainNode" needs to be exported by the entry point index.d.ts
 //

src/api.ts

@@ -8,8 +8,8 @@ const parser: peg.Parser = require('./internal/parser');
 /**
  * Generates a MfmNode tree from the MFM string.
 */
-export function parse(input: string): MfmNode[] {
+export function parse(input: string, opts: Partial<{ fnNameList: string[]; }> = {}): MfmNode[] {
-	const nodes = parser.parse(input, { startRule: 'fullParser' });
+	const nodes = parser.parse(input, { startRule: 'fullParser', fnNameList: opts.fnNameList });
 	return nodes;
 }
 

src/internal/parser.pegjs

@@ -56,6 +56,14 @@
 
 		return false;
 	}
+
+	function ensureFnName(name) {
+		if (!options.fnNameList) return true;
+		if (!Array.isArray(options.fnNameList)) {
+			error("options.fnNameList must be an array.");
+		}
+		return options.fnNameList.includes(name);
+	}
 }
 
 //
@@ -414,7 +422,7 @@ linkUrl
 // inline: fn
 
 fn
-	= "$[" name:$([a-z0-9_]i)+ args:fnArgs? _ content:(!("]") @inline)+ "]"
+	= "$[" name:$([a-z0-9_]i)+ &{ return ensureFnName(name); } args:fnArgs? _ content:(!("]") @inline)+ "]"
 {
 	args = args || {};
 	return FN(name, args, mergeText(content));

test/parser.ts

@@ -1050,6 +1050,24 @@ hoge`;
 			];
 			assert.deepStrictEqual(mfm.parse(input), output);
 		});
+
+		it('exists name in the fnNameList', () => {
+			const input = '$[spin.speed=1.1s text]';
+			const output = [
+				FN('spin', { speed: '1.1s' }, [
+					TEXT('text')
+				])
+			];
+			assert.deepStrictEqual(mfm.parse(input, { fnNameList: ['tada', 'spin'] }), output);
+		});
+
+		it('not exists name in the fnNameList', () => {
+			const input = '$[pope.speed=1.1s text]';
+			const output = [
+				TEXT('$[pope.speed=1.1s text]')
+			];
+			assert.deepStrictEqual(mfm.parse(input, { fnNameList: ['tada', 'spin'] }), output);
+		});
 	});
 
 	it('composite', () => {