Generate TSV file from JMDict XML data

parse.js

const fs = require('fs');

function getEntryStrings() {
    const ret = [];

    const text = fs.readFileSync('JMdict_e').toString();
    const openPos = [];
    const endPos = [];

    {
        const entryOpenTagRegExp = /<entry/g;

        for (let entryOpenMatch = entryOpenTagRegExp.exec(text); entryOpenMatch !== null; entryOpenMatch = entryOpenTagRegExp.exec(text)) {
            openPos.push(entryOpenMatch.index);
        }
    }

    {
        const entryEndTagRegExp = /<\/entry>/g;

        for (let entryEndMatch = entryEndTagRegExp.exec(text); entryEndMatch !== null; entryEndMatch = entryEndTagRegExp.exec(text)) {
            endPos.push(entryEndMatch.index);
        }
    }

    openPos.forEach((openAt, index) => {
        const endAt = endPos[index] + '</entry>'.length;

        ret.push(text.substring(openAt, endAt));
    });

    return ret;
}

{
    const rows = [];

    const entries = [];
    const allKeys = [];

    getEntryStrings().forEach((entryString) => {
        const textNodes = new Map();
        const elemStack = [];
        let curTerm = '';
        let isTagOpen = false;

        for (let iter = 0; iter < entryString.length; iter += 1) {
            if (!isTagOpen && entryString[iter] === '<') {
                if (/\S/.test(curTerm)) {
                    const key = elemStack.join(' ').replace(/^entry /, '');
                    const values = textNodes.get(key) || (() => {
                        const ret = [];

                        textNodes.set(key, ret);

                        return ret;
                    })();

                    values.push(curTerm);
                }

                curTerm = '';
                isTagOpen = true;

                continue;
            } else if (isTagOpen && entryString[iter] === '>') {
                if (curTerm[0] === '/') {
                    elemStack.pop();
                } else if (curTerm[curTerm.length - 1] !== '/') {
                    elemStack.push(/^[^\s]+/.exec(curTerm)[0]);
                }

                curTerm = '';
                isTagOpen = false;

                continue;
            } else {
                curTerm += entryString[iter];
            }
        }

        entries.push(textNodes);

        Array.from(textNodes.keys()).forEach((key) => {
            if (allKeys.indexOf(key) === -1 && key !== 'ent_seq') {
                allKeys.push(key);
            }
        });
    });

    rows.push(allKeys.join('\t'));

    entries.forEach((entry) => {
        const row = [entry.get('ent_seq')[0]];

        allKeys.forEach((key) => {
            row.push(entry.get(key) !== void 0 ? JSON.stringify(entry.get(key)) : '');
        });

        rows.push(row.join('\t'));
    });

    fs.writeFileSync('JMdict_e.tsv', rows.join('\n'));
}

Usage

Prerequisite

1. Both parse.js and JMdict_e (i.e. unzipped XML file) have to be located in a single directory.
2. NodeJS runtime environment. Note: Tested only in UNIX-like environments (including WSL).

Run

$ node parse.js

You will find JMdict_e.tsv in the working directory.