tts.js

var querystring = require('querystring');
var got = require('got');
var fs = require('fs');
var token = require('./token');
var languages = require('./languages');

// copy from https://github.com/zlargon/google-tts/blob/master/example/long-english-characters.js
// todo: could be optimized
function split(text) {
    const MAX = 200;  // Max string length

    const isSpace = (s, i) => /\s/.test(s.charAt(i));
    const lastIndexOfSpace = (s, left, right) => {
        for (let i = right; i >= left; i--) {
            if (isSpace(s, i)) return i;
        }
        return -1;  // not found
    };

    const result = [];
    const addResult = (text, start, end) => {
        const str = text.slice(start, end + 1);
        result.push(str);
    };

    let start = 0;
    for (; ;) {

        // check text's length
        if (text.length - start <= MAX) {
            addResult(text, start, text.length - 1);
            break;  // end of text
        }

        // check whether the word is cut in the middle.
        let end = start + MAX - 1;
        if (isSpace(text, end) || isSpace(text, end + 1)) {
            addResult(text, start, end);
            start = end + 1;
            continue;
        }

        // find last index of space
        end = lastIndexOfSpace(text, start, end);
        if (end === -1) {
            throw new Error('the amount of single word is over that 200.');
        }

        // add result
        addResult(text, start, end);
        start = end + 1;
    }

    return result;
}

function multi(arr, opts) {
    return single(arr.shift(), opts).then(function () {
        if (arr.length > 0) return multi(arr, opts);
    });
}

function single(text, opts) {
    opts = opts || {};

    return token.get(text, opts).then(function (token) {
        var url = opts.domain + '/translate_tts';
        var data = {
            client: opts.client || 't',
            tl: opts.to,
            ie: 'UTF-8',
            idx: 0,
            total: 1,
            textlen: text.length,
            q: text
        };
        data[token.name] = token.value;
        return url + '?' + querystring.stringify(data);
    }).then(function (url) {
        return got(url, {encoding: null, agent: opts.agent}).then(function (res) {
            fs.appendFile(opts.file, res.body, function (err) {
                if (err) throw err;
            });
        }).catch(function (err) {
            err.message += `\nUrl: ${url}`;
            if (err.statusCode !== undefined && err.statusCode !== 200) {
                err.code = 'BAD_REQUEST';
            } else {
                err.code = 'BAD_NETWORK';
            }
            throw err;
        });
    });
}

module.exports.single = single;
module.exports.multi = multi;
module.exports.split = split;