token_mapper.js

const translateToken = require('./translate_token.js')
/**
 * @param {array} tokens
 * @param {string} from
 * @param {string} to
 * @param {object} map
 * @returns {object}
 */
module.exports = async (tokens, from, to, map) => {
    const allPromises = [];

    var fromLangIdx, toLangIdx;

    if (!map["languages"]) {
        map["languages"] = []
    }

    if (!map["tokens"]) {
        map["tokens"] = []
    }

    fromLangIdx = map["languages"].indexOf(from);
    toLangIdx = map["languages"].indexOf(to);
    if (fromLangIdx === -1) { // from language not found
        fromLangIdx = map["languages"].length;
        map["languages"].push(from);
        map["tokens"].forEach(row => {
            row.push(null)
        });
    }
    if (toLangIdx === -1) { // to language not found
        toLangIdx = map["languages"].length;
        map["languages"].push(to);
        map["tokens"].forEach(row => {
            row.push(null)
        });
    }

    for (let i = 0; i < tokens.length; i++) {
        let inDict = false;
        map["tokens"].forEach(row => {
            if (row[toLangIdx] && row[fromLangIdx] === tokens[i].value) {
                tokens[i].translated = row[toLangIdx];
                inDict = true;
            }
        });
        if (!inDict) {
            allPromises.push(translateToken(tokens[i], i, from, to));
        }
    }
    var results = await Promise.all(allPromises);
    results.forEach(result => {
        var token = result.token;
        tokens[result.index] = token;

        // Update map with new language translation of a token that
        var found = false;
        for (var j = 0; j < map["tokens"].length; j++) {
            if (map["tokens"][j][fromLangIdx] === token.value) {
                map["tokens"][j][toLangIdx] = token.translated;
                found = true;
                break;
            }
        }
        if (!found) {
            // Completely new token: push new row
            row = new Array(map["languages"].length).fill(null);
            row[fromLangIdx] = token.value;
            row[toLangIdx] = token.translated;
            map["tokens"].push(row);
        }
    });
    return {"tokens": tokens, "map": map};
}