async-some

some

Short-circuited async Array.prototype.some implementation.

Serially evaluates a list of values from a JS array or arraylike against an asynchronous predicate, terminating on the first truthy value. If the predicate encounters an error, pass it to the completion callback. Otherwise, pass the truthy value passed by the predicate, or false if no truthy value was passed.

Is Zalgo-proof, browser-safe, and pretty efficient.

Usage

var some = require("async-some");
var resolve = require("path").resolve;
var stat = require("fs").stat;
var readFileSync = require("fs").readFileSync;

some(["apple", "seaweed", "ham", "quince"], porkDetector, function (error, match) {
  if (error) return console.error(error);

  if (match) return console.dir(JSON.parse(readFileSync(match)));

  console.error("time to buy more Sporkle™!");
});

var PREFIX = resolve(__dirname, "../pork_store");
function porkDetector(value, cb) {
  var path = resolve(PREFIX, value + ".json");
  stat(path, function (er, stat) {
    if (er) {
      if (er.code === "ENOENT") return cb(null, false);

      return cb(er);
    }

    cb(er, path);
  });
}

some(list, test, callback)

• list {Object} An arraylike (either an Array or the arguments arraylike) to be checked.
• test {Function} The predicate against which the elements of list will be tested. Takes two parameters:
  • element {any} The element of the list to be tested.
  • callback {Function} The continuation to be called once the test is complete. Takes (again) two values:
    • error {Error} Any errors that the predicate encountered.
    • value {any} A truthy value. A non-falsy result terminates checking the entire list.
• callback {Function} The callback to invoke when either a value has been found or the entire input list has been processed with no result. Is invoked with the traditional two parameters:
  • error {Error} Errors that were encountered during the evaluation of some().
  • match {any} Value successfully matched by test, if any.