1.下载ffmpeg
http://ffmpeg.org/
2.引入child_process模块

const exec = require('child_process').exec;

3.直接拼接音频

//nanStr=concat:./src/files/nv1/1.mp3|./src/files/nv1/1.mp3
//nanCopy=放想存的路径
exec(`ffmpeg -i "${nanStr}" -acodec copy "${nanCopy}" `, () => {
    //这里放合成后做的事
    tencentUpload.uploadVideo({ openid, path, pathTitle, sexual: 'nan' }).then(res => {
         fs.unlink(nanCopy, (err) => { })
    })  
});