add api doc

src/api.ts

@@ -4,16 +4,25 @@ import { stringifyNode, stringifyTree } from './util';
 
 const parser: peg.Parser = require('./parser');
 
+/**
+ * generate a node tree from the MFM string.
+*/
 export function parse(input: string): MfmNode[] {
 	const nodes = parser.parse(input, { startRule: 'fullParser' });
 	return nodes;
 }
 
+/**
+ * generate a node tree of plain from the MFM string.
+*/
 export function parsePlain(input: string): MfmPlainNode[] {
 	const nodes = parser.parse(input, { startRule: 'plainParser' });
 	return nodes;
 }
 
+/**
+ * generate a MFM string from the node tree.
+*/
 export function toString(tree: MfmNode[]): string
 export function toString(node: MfmNode): string
 export function toString(node: MfmNode | MfmNode[]): string {
@@ -25,6 +34,9 @@ export function toString(node: MfmNode | MfmNode[]): string {
 	}
 }
 
+/**
+ * Inspects the node tree.
+*/
 export function inspect(nodes: MfmNode[], action: (node: MfmNode) => void): void {
 	for (const node of nodes) {
 		action(node);
@@ -34,6 +46,10 @@ export function inspect(nodes: MfmNode[], action: (node: MfmNode) => void): void
 	}
 }
 
+/**
+ * Inspects the node tree and returns as an array the nodes that match the conditions
+ * of the predicate function.
+*/
 export function extract(nodes: MfmNode[], predicate: (node: MfmNode) => boolean): MfmNode[] {
 	const dest = [] as MfmNode[];