Subprocess Spawning: running other files using subprocesses

An example of a subprocess being spawned to run specified files using CLI flags.

import { parseArgs } from "jsr:@std/cli";

Grab the file name using the parseArgs function from the standard library. If no file is provided, exit with an error.

import { expandGlob } from "jsr:@std/fs";

const flags = parseArgs(Deno.args, {
  string: ["file"],
  default: {
    file: "",
  },
});

if (!flags.file) {
  console.error("No file provided");
  Deno.exit(1);
}

Use expandGlob to find all files matching the provided filename.

const FilesList = await Array.fromAsync(
  expandGlob(`**/*${flags.file}*`, { root: "." }),
);

const files = FilesList.filter((files) => files.name.includes(flags.file));

If no files are found, exit with an error.

if (files.length === 0) {
  console.error("No files found");
  Deno.exit(1);
}

If multiple files are found, exit with an error.

if (files.length > 1) {
  console.error("Multiple files found");
  Deno.exit(1);
}

const file = files[0];

Use the Deno.Command class to create a new command that will run the specified file.

const command = new Deno.Command(Deno.execPath(), {
  args: [file?.path],
});

Try to spawn the command and catch any errors that may occur. Wait for the subprocess to finish and log the exit code.

try {
  const child = command.spawn();

  child.ref();
} catch (error) {
  console.error("Error while running the file: ", error);
  Deno.exit(4);
}

Run this example locally using the Deno CLI:

deno run --allow-net --allow-run --allow-read https://docs.deno.com/examples/scripts/subprocess_running_files.ts

Subprocess Spawning: running other files using subprocesses

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