Complete files in a different directory in zsh - autocomplete

Question

Does the compadd command for ZSH not support completion when some characters are entered？
I have a executable file called 'index_for_test.js',and i add a shell script to .zshrc.
$PATH:
/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Users/hanqing/Development/compadd-test
the index_for_test.js at the root of /Users/hanqing/Development/compadd-test
./
├── dir1
│ ├── a.js
│ └── b.js
├── dir2
│ ├── a.ts
│ └── b.ts
└── index_for_test.js
total 24
drwxr-xr-x 6 hanqing staff 192 11 4 13:45 .
drwxr-xr-x 10 hanqing staff 320 11 4 13:42 ..
-rw-r--r--# 1 hanqing staff 6148 11 4 14:04 .DS_Store
drwxr-xr-x 4 hanqing staff 128 11 4 13:43 dir1
drwxr-xr-x 4 hanqing staff 128 11 4 13:43 dir2
-rwxr-xr-x 1 hanqing staff 155 11 4 13:50 index_for_test.js
// index_for_test.js
#! /usr/bin/env node
const fs =require('fs')
const path=require('path')
const files=fs.readdirSync(path.join(process.cwd()))
console.log(files.join('\n'))
the script be added to .zshrc :
_index_for_test_completion() {
local abc=(`index_for_test.js`)
echo '\nabc:\n'
echo $abc'\n'
compadd -- $abc
}
compdef _index_for_test_completion index_for_test.js
When input index_for_test.js followed by input a space then press tab, it work find.But when input index_for_test.js ../ then press tab,it does not show completion list, even if compadd accept the arguments.
Image:
normal: index_for_test.js
error: index_for_test.js ../
Expect
If this is my mistake,please let me know the reason,thanks.
In addition,if the behavior is right,I wonder that how to achieve completion like cd command;
behavior of cd

Answer 1

index_for_test.js only prints names of files in the current directory. A file name in the current directory cannot start with ../, so there is no completion starting with ../.
If you want to complete files in a directory, you need to pass this directory to your completion script, and have it work in that directory.
In addition, you should complete directory names inside zsh, if all directories may potentially contain interesting files. If you want to allow only certain directories, have your script complete directories.
In addition, your script is broken when file names contain whitespace. Use a null byte as the separator: file names can't contain null bytes.
Untested code. May need some tweaking.
#!/usr/bin/env node
const fs = require('fs');
const path = require('path');
const files = fs.readdirSync(process.argv[2]);
console.log(files.join('\0'))
_index_for_test_completion() {
local dir=$words[CURRENT] files
if [[ ! -d $dir ]]; then dir=$dir:h; fi
files=(${(ps:\0:)$(index_for_test.js $dir))
print -lr '' abc: $files
if [[ $dir != $words[CURRENT] ]]; then dir+="/"; fi
compadd -- $^dir$files
}
compdef _index_for_test_completion index_for_test.js