type-func

Install

npm install --save type-func

About

This is a collection of functions that return functions that return certain types of values.

The signature is:

typeFunc(func|value, default|undefined)

typeFunc is one of these types.

• boolean(func|boolean, default|undefined) -> fn(...args)
• integer(func|integer, default|undefined) -> fn(...args)
• string(func|string, default|undefined) -> fn(...args)

The fn function returned by one of the above type functions returns the value of that type.

Example:

import { boolean } from 'type-func';
let bool1 = boolean(true);
 
let bool2 = boolean(()=>false);
 

The variables bool1, and bool2 in the above example are functions that return a boolean.

All returned types are converted from the input to the respective type.

Example:

import { boolean } from 'type-func';
let zero1 = boolean(0);
console.log(zero1());// prints false
let zero2 = boolean(()=>0);
console.log(zero2());// also prints false

When undefined is passed a default value is used. If there is no default value set then undefined will be converted as needed.

import { boolean } from 'type-func';
 
let defaultToFalse = boolean(undefined, false)
console.log(defaultToFalse());// prints false
let undef = boolean(undefined);
console.log(undef()); // prints false

What's this good for?

Default options. Examples:

import { boolean } from 'type-func';
 
function myClass(options){
    this.opt = boolean(options.opt, false);
}

import { boolean } from 'type-func';
 
function myClass({opt: opt} = {opt: false}){
    this.opt = boolean(options.opt);
}

import { boolean } from 'type-func';
 
function myClass(opt = boolean(true)){
    this.opt = boolean(opt);
}

About

Just some helper functions that return consistent types.