Unused node.props and node.children are not generated.

src/node.ts

@@ -4,7 +4,7 @@ export type MfmBlock = MfmQuote | MfmSearch | MfmCodeBlock | MfmMathBlock | MfmC
 
 export type MfmQuote = {
 	type: 'quote';
-	props: { };
+	props?: { };
 	children: MfmNode[];
 };
 
@@ -14,7 +14,7 @@ export type MfmSearch = {
 		q: string;
 		content: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmCodeBlock = {
@@ -23,7 +23,7 @@ export type MfmCodeBlock = {
 		code: string;
 		lang: string | null;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmMathBlock = {
@@ -31,14 +31,12 @@ export type MfmMathBlock = {
 	props: {
 		formula: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmCenter = {
 	type: 'center';
-	props: {
-
-	};
+	props?: { };
 	children: MfmInline[];
 };
 
@@ -51,30 +49,30 @@ export type MfmEmoji = {
 		emoji?: string;
 		name?: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmBold = {
 	type: 'bold';
-	props: { };
+	props?: { };
 	children: MfmInline[];
 };
 
 export type MfmSmall = {
 	type: 'small';
-	props: { };
+	props?: { };
 	children: MfmInline[];
 };
 
 export type MfmItalic = {
 	type: 'italic';
-	props: { };
+	props?: { };
 	children: MfmInline[];
 };
 
 export type MfmStrike = {
 	type: 'strike';
-	props: { };
+	props?: { };
 	children: MfmInline[];
 };
 
@@ -83,7 +81,7 @@ export type MfmInlineCode = {
 	props: {
 		code: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmMathInline = {
@@ -91,7 +89,7 @@ export type MfmMathInline = {
 	props: {
 		formula: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmMention = {
@@ -101,7 +99,7 @@ export type MfmMention = {
 		host: string | null;
 		acct: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmHashtag = {
@@ -109,7 +107,7 @@ export type MfmHashtag = {
 	props: {
 		hashtag: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmUrl = {
@@ -117,7 +115,7 @@ export type MfmUrl = {
 	props: {
 		url: string;
 	};
-	children: [];
+	children?: [];
 };
 
 export type MfmLink = {
@@ -143,5 +141,5 @@ export type MfmText = {
 	props: {
 		text: string;
 	};
-	children: [];
+	children?: [];
 };

src/parser.pegjs

@@ -65,7 +65,7 @@ quote
 {
 	const lines = [head, ...tails];
 	const children = applyParser(lines.join('\n'), 'fullParser');
-	return createNode('quote', { }, children);
+	return createNode('quote', null, children);
 }
 
 quoteLine
@@ -131,7 +131,7 @@ mathBlockLine
 center
 	= BEGIN "<center>" content:(!("</center>" END) i:inline { return i; })+ "</center>" END
 {
-	return createNode('center', { }, mergeText(content));
+	return createNode('center', null, mergeText(content));
 }
 
 //
@@ -191,12 +191,12 @@ big
 bold
 	= "**" content:(!"**" i:inline { return i; })+ "**"
 {
-	return createNode('bold', { }, mergeText(content));
+	return createNode('bold', null, mergeText(content));
 }
 	/ "__" content:$(!"__" c:([a-z0-9]i / _) { return c; })+ "__"
 {
 	const parsedContent = applyParser(content, 'inlineParser');
-	return createNode('bold', { }, parsedContent);
+	return createNode('bold', null, parsedContent);
 }
 
 // inline: small
@@ -204,7 +204,7 @@ bold
 small
 	= "<small>" content:(!"</small>" i:inline { return i; })+ "</small>"
 {
-	return createNode('small', { }, mergeText(content));
+	return createNode('small', null, mergeText(content));
 }
 
 // inline: italic
@@ -212,17 +212,17 @@ small
 italic
 	= "<i>" content:(!"</i>" i:inline { return i; })+ "</i>"
 {
-	return createNode('italic', { }, mergeText(content));
+	return createNode('italic', null, mergeText(content));
 }
 	/ "*" content:$(!"*" ([a-z0-9]i / _))+ "*"
 {
 	const parsedContent = applyParser(content, 'inlineParser');
-	return createNode('italic', { }, parsedContent);
+	return createNode('italic', null, parsedContent);
 }
 	/ "_" content:$(!"_" ([a-z0-9]i / _))+ "_"
 {
 	const parsedContent = applyParser(content, 'inlineParser');
-	return createNode('italic', { }, parsedContent);
+	return createNode('italic', null, parsedContent);
 }
 
 // inline: strike
@@ -230,7 +230,7 @@ italic
 strike
 	= "~~" content:(!("~" / LF) i:inline { return i; })+ "~~"
 {
-	return createNode('strike', { }, mergeText(content));
+	return createNode('strike', null, mergeText(content));
 }
 
 // inline: inlineCode

src/util.ts

 import { MfmNode, MfmText } from './node';
 
-export function createNode(type: string, props: Record<string, any>, children?: MfmNode[]): MfmNode {
-	props = props ?? {};
-	children = children ?? [];
-	const node = { type, props, children } as MfmNode;
+export function createNode(type: string, props?: Record<string, any>, children?: MfmNode[]): MfmNode {
+	const node: any = { type };
+	if (props != null) {
+		node.props = props;
+	}
+	if (children != null) {
+		node.children = children;
+	}
 	return node;
 }
 
@@ -30,10 +34,14 @@ export function mergeGroupedTrees(groupedTrees: MfmNode[][]): MfmNode[] {
 	return groupedTrees.reduce((acc, val) => acc.concat(val), ([] as MfmNode[]));
 }
 
-export function mergeText(trees: MfmNode[], recursive?: boolean): MfmNode[] {
+export function mergeText(trees: MfmNode[] | undefined, recursive?: boolean): MfmNode[] | undefined {
 	let dest: MfmNode[];
 	let groupes: MfmNode[][];
 
+	if (trees == null) {
+		return trees;
+	}
+
 	// group trees
 	groupes = groupContinuous(trees, (prev, current) => prev.type == current.type);
 
@@ -52,10 +60,15 @@ export function mergeText(trees: MfmNode[], recursive?: boolean): MfmNode[] {
 	// merge groups
 	dest = mergeGroupedTrees(groupes);
 
-	return dest.map(tree => {
-		// apply recursively to children
-		return createNode(tree.type, tree.props, recursive ? mergeText(tree.children) : tree.children);
-	});
+	if (recursive) {
+		return dest.map(tree => {
+			// apply recursively to children
+			return createNode(tree.type, tree.props, recursive ? mergeText(tree.children) : tree.children);
+		});
+	}
+	else {
+		return dest;
+	}
 }
 
 //

test/node.ts

@@ -4,23 +4,23 @@ import {
 	MfmNode, MfmQuote, MfmSearch, MfmSmall, MfmStrike, MfmText, MfmUrl
 } from '../built';
 
-export const QUOTE = (children: MfmNode[]): MfmQuote => { return { type:'quote', props: { }, children }; };
-export const SEARCH = (q: string, content: string): MfmSearch => { return { type:'search', props: { q, content }, children: [] }; };
-export const CODE_BLOCK = (code: string, lang: string | null): MfmCodeBlock => { return { type:'blockCode', props: { code, lang }, children: [] }; };
-export const MATH_BLOCK = (formula: string): MfmMathBlock => { return { type:'mathBlock', props: { formula }, children: [] }; };
-export const CENTER = (children: MfmInline[]): MfmCenter => { return { type:'center', props: { }, children }; };
+export const QUOTE = (children: MfmNode[]): MfmQuote => { return { type:'quote', children }; };
+export const SEARCH = (q: string, content: string): MfmSearch => { return { type:'search', props: { q, content } }; };
+export const CODE_BLOCK = (code: string, lang: string | null): MfmCodeBlock => { return { type:'blockCode', props: { code, lang } }; };
+export const MATH_BLOCK = (formula: string): MfmMathBlock => { return { type:'mathBlock', props: { formula } }; };
+export const CENTER = (children: MfmInline[]): MfmCenter => { return { type:'center', children }; };
 
-export const BOLD = (children: MfmInline[]): MfmBold => { return { type:'bold', props: { }, children }; };
-export const SMALL = (children: MfmInline[]): MfmSmall => { return { type:'small', props: { }, children }; };
-export const ITALIC = (children: MfmInline[]): MfmItalic => { return { type:'italic', props: { }, children }; };
-export const STRIKE = (children: MfmInline[]): MfmStrike => { return { type:'strike', props: { }, children }; };
-export const INLINE_CODE = (code: string): MfmInlineCode => { return { type:'inlineCode', props: { code }, children: [] }; };
-export const MATH_INLINE = (formula: string): MfmMathInline => { return { type:'mathInline', props: { formula }, children: [] }; };
-export const MENTION = (username: string, host: string | null, acct: string): MfmMention => { return { type:'mention', props: { username, host, acct }, children: [] }; };
-export const HASHTAG = (value: string): MfmHashtag => { return { type:'hashtag', props: { hashtag: value }, children: [] }; };
-export const N_URL = (value: string): MfmUrl => { return { type:'url', props: { url: value }, children: [] }; };
+export const BOLD = (children: MfmInline[]): MfmBold => { return { type:'bold', children }; };
+export const SMALL = (children: MfmInline[]): MfmSmall => { return { type:'small', children }; };
+export const ITALIC = (children: MfmInline[]): MfmItalic => { return { type:'italic', children }; };
+export const STRIKE = (children: MfmInline[]): MfmStrike => { return { type:'strike', children }; };
+export const INLINE_CODE = (code: string): MfmInlineCode => { return { type:'inlineCode', props: { code } }; };
+export const MATH_INLINE = (formula: string): MfmMathInline => { return { type:'mathInline', props: { formula } }; };
+export const MENTION = (username: string, host: string | null, acct: string): MfmMention => { return { type:'mention', props: { username, host, acct } }; };
+export const HASHTAG = (value: string): MfmHashtag => { return { type:'hashtag', props: { hashtag: value } }; };
+export const N_URL = (value: string): MfmUrl => { return { type:'url', props: { url: value } }; };
 export const LINK = (silent: boolean, url: string, children: MfmInline[]): MfmLink => { return { type:'link', props: { silent, url }, children }; };
-export const CUSTOM_EMOJI = (name: string): MfmEmoji => { return { type:'emoji', props: { name: name }, children: [] }; };
+export const CUSTOM_EMOJI = (name: string): MfmEmoji => { return { type:'emoji', props: { name: name } }; };
 export const FN = (name: string, args: MfmFn['props']['args'], children: MfmFn['children']): MfmFn => { return { type:'fn', props: { name, args }, children }; };
-export const UNI_EMOJI = (value: string): MfmEmoji => { return { type:'emoji', props: { emoji: value }, children: [] }; };
-export const TEXT = (value: string): MfmText => { return { type:'text', props: { text: value }, children: [] }; };
+export const UNI_EMOJI = (value: string): MfmEmoji => { return { type:'emoji', props: { emoji: value } }; };
+export const TEXT = (value: string): MfmText => { return { type:'text', props: { text: value } }; };