@cursormove/flow-is-helpers NPM

Predicate `truthy` Function via `%check`

Description

This is a Flow helper library for Lodash is and additional Flow predicate type %checks functions. Simply put, this library contains converted truthy predicate functions through the use of Flow %check annotations. By doing so it aids and increases the ability for The Flow Parser to properly check the defined predicate functions.

Why?

Flow and Lodash's predicate functions (is***) don't work well together (if at all in some cases) resulting in duplicate logic. Ideally a fix will be implemented into the main flow-type Lodash library but until that time comes (if ever) this library acts as a stopgap solution. In addition, this library includes some helpful custom predicate check functions.

Install

# npm
npm i --save @cursormove/flow-is-helpers

# yarn
yarn add @cursormove/flow-is-helpers

Usage

This Library is a drop-in replacement for Lodash's predicate functions. You should be able to just swap out Lodash predicate functions like isString with this library. I recommend you take a quick look at the code base just so you have a better understanding of what is going on but the gist of it is pretty simple.

import {
  isString,
} from '@cursormove/flow-is-helpers';

// Flow Type Check & truthy predicate function check
const hello = (val: string) => isString(val) ? `Hello ${val}` : 'Hello Nobody';

hello('World'); // 'Hello World' 
hello(null); // 'Hello Nobody'

API 🠲 Custom Checks

Array Checks

isEmptyArray 🠲 Checks if Array is empty.
isNonEmptyArray 🠲 Checks if Array is empty.

Function Checks

isPromise 🠲 Checks if Function type is a Promise.
isAsync 🠲 Checks if Function type is Async.
isGenerator 🠲 Checks if Function type is a Generator Iterator.
isGeneratorFunction 🠲 Checks if Function type is a Generator.

Plain Object Checks (Not ObjectLike)

isEmptyObject 🠲 Checks if Object is empty.
isNonEmptyObject 🠲 Checks if Object is not empty.
isFrozen 🠲 Checks if Object is Frozen.
isFrozen 🠲 Checks if Object is Sealed.
isFrozen 🠲 Checks if Object is Extensible.

String Checks

isEmptyString 🠲 Checks if String is empty.
isNonEmptyString 🠲 Checks if String is not empty.

Number Checks

isNan 🠲 Checks if value is not a Number.
isInfinity 🠲 Checks if value is either Number.NEGATIVE_INFINITY or Number.POSITIVE_INFINITY.

Nil Checks

isNotNil 🠲 Opposite of Lodash's isNil in that it's not null or undefined.

Miscellaneous Checks

isIterable 🠲 Checks if value is an Iterable
isAction 🠲 Checks if value is a Redux Action

API 🠲 Lodash Checks

Includes all Lodash is Predicate Functions

Best, te

flow flow-helpers flow-is-helpers flow-checks flow-lodash flow-typed @cursormove

@babel/runtime core-js lodash

@infinitebrahmanuniverse/nolb-_cur @everything-registry/sub-chunk-209 @zalastax/nolb-_cur

2.1.0

7 years ago

Predicate truthy Function via %check