function writeTop(d, loc) {
            if (d.indexOf('\n') != -1) {
                throw 'Can not write content having \\n'
            }
            this.chunks.unshift(chunk(d, loc))
        }
function writeTop(d, loc) {
            if (d.indexOf('\n') != -1) {
                throw 'Can not write content having \\n'
            }
            this.chunks.unshift(chunk(d, loc))
        }
function writeTop ( d , loc ) { if ( d . indexOf ( '\n' ) != - 1 ) { throw 'Can not write content having \\n' } this . chunks . unshift ( chunk ( d , loc ) ) }
unshift a new chunk
unshift a new chunk