Confusion about the composition of the `cmd` parameter used in Deno.run() - deno

Question

I tried to use Deno as a replacement for shell script, but got stuck.
I attempted to use Deno/Typescript to carry out the equivalent job as this:
docker run \
-d \
-v pgdata:/var/lib/postgresql/data \
--name pg \
-e POSTGRES_PASSWORD=123456 \
--rm \
-p 5432:5432 \
postgres
ts code looks like this:
function runCmd(s: string[]): Deno.Process {
return Deno.run({ cmd: s, stdout: "piped", stderr: "piped" })
}
function runPg() {
const cmd = [
"docker",
`run -d -v ${VOLUME}:/var/lib/postgresql/data --name pg -e POSTGRES_PASSWORD=${PASSWORD} --rm -p 5432:5432 postgres`
];
return runCmd(cmd);
}
add execution bit to this ts file and run it in terminal:
after this, I tried
function runPg() {
const cmd = [
"docker",
"run",
`-d -v ${VOLUME}:/var/lib/postgresql/data --name pg -e POSTGRES_PASSWORD=${PASSWORD} --rm -p 5432:5432 postgres`
];
return runCmd(cmd);
}
move out subcommand run from command options.
I got this:
I guess that Deno.run doesn't simply concatenate the passed-in string of command particles, but I cannot find enough information on this subject in order to fix the issue.
I haven't gone through the rust source code on this API, but I thought it's better to ask for help before trying the hard way.

Answer 1

You need to specify each part of the command as a separate string in the cmd array:
function runPg() {
const cmd = [
"docker",
"run",
"-d",
"-v",
`${VOLUME}:/var/lib/postgresql/data`,
"--name",
"pg",
"-e",
`POSTGRES_PASSWORD=${PASSWORD}`,
"--rm",
"-p",
"5432:5432",
"postgres"
];
return runCmd(cmd);
}
This will send run as the first argument to docker instead of sending run -d … as the first argument.
You can also build your command as a single string and then use split(" ") as long as no arguments contain spaces.

Answer 2

a follow up on my trial-n-error journey on this top.
While reading a book about unix shell programming, it points out a way to help the shell differentiate the space in identifier and the space as delimiter. When one tries to cat a file named a b (there is a space in between), the command should be cat a\ b or, using quotes, cat 'a b'.
This gives me an idea why my command does not work in Deno. See, each item in the cmd string list is an identifier, when I mix up delimiter-space with identifiers, the command is interpreted in the wrong way.
For example.
If I'd like to cat a file named a b. In Deno.run, I need to use { cmd: ["cat", "a b"] }.
If I'd like to cat two files named a and b. In Deno.run, I need to use { cmd: ["cat", "a", "b"] }.
Just remember that space in a command particle counts as a part of that term.