Vue.js on Debian 9 installation woes

Question

I'm trying to install Vue.js on my Debian 9 OS and I'm getting this error message: Illegal instruction] - rollbackFailedOptional: verb npm-session 1fd93108cdc88b2

when I do this command: npm install vue

The version of npm is 6.13.7

I've had problems with sudo apt-get update, which causes the following error:

Ign:25 http://ppa.launchpad.net/ondrej/php/ubuntu focal/main DEP-11 64x64 Icons
Fetched 15.4 kB in 8s (1,813 B/s)                   
Reading package lists... Done
W: The repository 'http://ppa.launchpad.net/ondrej/php/ubuntu focal Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://ppa.launchpad.net/webupd8team/brackets/ubuntu bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C2518248EEA14886
W: The repository 'http://ppa.launchpad.net/webupd8team/brackets/ubuntu bionic InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://ppa.launchpad.net/ondrej/php/ubuntu/dists/focal/main/source/Sources  404  Not Found [IP: 91.189.95.83 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.

I searched StackExchange and the web for this error and have tried the associated solutions (with no success)

Answer 1

change directory to /etc/apt/sources.list.d then remove Ondrej and Barckets PPA, also remove php version and barckets (packages belongs to Ubuntu Bionic and Focal).

To install Barckets download the deb file from here:

sudo apt install gdebi
wget https://github.com/adobe/brackets/releases/download/release-1.14.1/Brackets.Release.1.14.1.64-bit.deb
sudo gdebi Brackets.Release.1.14.1.64-bit.deb

To add ondrej repository use:

sudo apt install apt-transport-https lsb-release ca-certificates curl
sudo wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
printf "deb https://packages.sury.org/php/ $(lsb_release -sc) main" |sudo tee  /etc/apt/sources.list.d/php.list
sudo apt update

vue and vue-cli install:

npm install -g npm
npm install -g vue
npm install -g @vue/cli