naive-org-mode-parser.ts

import * as fs from 'fs';

const data = fs.readFileSync('./research.org', 'utf-8');

enum NodeType { HeaderType, TextType };
type NodeLevel = number | null;
type NodeValue = string | null;

interface Node {
    nodeType: NodeType;
    level:    NodeLevel;
    value:    NodeValue;
    childs:   Node[];
}

let root: Node = {
    nodeType: NodeType.TextType,
    level: null,
    value: null,
    childs: []
};

const parseHeader = (line: string): Node | null => {
    let starCount = line.split('').reduce((count: number, char: string) => count + (char === '*' ? 1 : 0), 0);
    let headerValue = line.split('').reduce((value: string, char: string) => (char !== '*' ? value + char : value), '');
    if (!starCount) return null;
    return {
        nodeType: NodeType.HeaderType,
        level: starCount,
        value: headerValue.trim(),
        childs: []
    };
};

const parseText = (line: string): Node | null => {
    if (line[0] === '*') return null;
    let value = line.trim();
    if (!value.length) return null;
    return {
        nodeType: NodeType.TextType,
        level: -1,
        value: value,
        childs: []
    };
};

let parent: Node = root;
let current: Node = root;

const lines: string[] = data.split('\n');
lines.forEach((line: string) => {
    let header = parseHeader(line);
    if (header) {
        if (current.level < header.level) {
            current.childs.push(header);
            parent = current;
            current = header;
        } else if (current.level === header.level) {
            parent.childs.push(header);
            current = header;
        } else if (current.level > header.level) {
            current = parent;
            current.childs.push(header);
            current = header;
        }
    } else {
        let text = parseText(line);
        if (text) {
            current.childs.push(text);
        }
    }
});

console.log(JSON.stringify(root));