node-tailor/lib/streams/content-length-stream.js

Tailor assembles a web page from multiple fragments

'use strict';

const stream = require('stream');

module.exports = class ContentLengthStream extends stream.Transform {
    constructor(callback) {
        super();
        this.callback = callback;
        this.contentSize = 0;
    }

    _transform(chunk, encoding, done) {
        this.contentSize += chunk.length;
        done(null, chunk);
    }

    _flush(done) {
        this.callback(this.contentSize);
        done();
    }
};