[Feature Request] Option to ignore file existence of static (non-glob) patterns

[swebra]

Currently fast-glob silently omits any input files which do not exist from its output; this makes sense given that glob patterns need to be dropped in favor of the corresponding found files. However, in the context of a CLI tool for example, one might want to warn a user if a static pattern was not found given that a static path may be more intentional. As far as I can tell, because of the omission behavior, there isn't a super elegant way to achieve this.

If you pass a file list through fast-glob and intend to throw warnings when you read said files, any non-existing files will already be omitted by fast-glob:

import { sync } from "fast-glob";
import { readFileSync } from "fs";

let inputPaths = ["path/does/not.exist", "/some/*/glob/**"];
inputPaths = sync(inputPaths, { unique: true }); // expand globs

inputPaths.forEach((filePath) => {
  try {
    const contents = readFileSync(filePath, "utf-8");
    // Do something with contents
  } catch (err) {
    console.warn(`Could not open ${filePath}`);
  }
});

// will never warn about path/does/not.exist because `sync` call (line 5) strips it away

You can instead use isDynamicPattern to only pass dynamic patterns to sync...

import { isDynamicPattern, sync } from "fast-glob";
import { readFileSync } from "fs";

function expandInputPaths(paths: string[]): string[] {
  const splitPaths = paths.reduce(
    (acc, path) => {
      acc[isDynamicPattern(path) ? "glob" : "globless"].push(path);
      return acc;
    },
    { glob: [], globless: [] } as { glob: string[]; globless: string[] }
  );

  const recombinedPaths = sync(splitPaths["glob"]).concat(splitPaths["globless"]);
  return [...new Set(recombinedPaths)]; // remove duplicates
}

let inputPaths = ["path/does/not.exist", "/some/*/glob/**"];
inputPaths = expandInputPaths(inputPaths); // expand globs

inputPaths.forEach((filePath) => {
  try {
    const contents = readFileSync(filePath, "utf-8");
    // Do something with contents
  } catch (err) {
    console.warn(`Could not open ${filePath}`);
  }
});

... but a) this has to repeat the iteration and checks that sync is already doing, and b) this doesn't allow you to use the nice fast-glob options like unique (because you aren't passing all the files to fast-glob)

I'm thinking if fast-glob had a way to keep the static patterns which don't exist, the first example would work. I'm welcome to suggestions of other ways to approach this as well.