This library is inspired by functional programming - Clojure

The minimum and most straightforward way to check if command exists and where the executable is, without spawning child_process.

Check if artifact exists in remote maven repository

This example implements a Bloom filter in Python, a probabilistic data structure for fast membership testing. Items are added using multiple hash functions that set bits in a fixed-size array. Membership checks return definitely not present or possibly present, with false positives possible. The source code is part of the 127 algorithms collection.

Joining Tables in SQL

mongoose validation to ensure referenced object id exists

🪐 The missing fs.promises.exists(). Also supports case-sensitive/insensitive file paths.

Node module to check if a command-line command exists.

Returns true if a npm package exists in global node_modules.

DEPRECATED REPO!! New place at https://github.com/tunnckocore/opensource! Next release soon will be published! Return positive value if any of passed values exists in array, or optionally an index.

A validation module checking for Gmail account existence

Laravel validation rule to check if a custom route key exists.

🧩 Pattern matching objects

Check if a name exists on npm registry

Elaborated examples concerning functional concepts e.g. gadt, eadt, church encodings

[OBSOLETE] Checks if an e-mail address exists or not

Returns existence of key or value in an object

🧲 Provides ways of properly checking if a path exists inside a given array of files/directories both on Windows and UNIX-like operating systems. 🗺

Solves routine array actions: get value by key if exists or default; set key if not exists. PHP 5, 7

👐 Extended open command with default dir set to current