Type functions

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1.0.37 years ago7 years agoMinified + gzip package size for type-func in KB



npm install --save type-func


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.
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.
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);


Just some helper functions that return consistent types.