EVL

😈 Function fallback when error.

Likes NVL but for Error fallback.

Installation

Via NPM:

npm install evl

Via Yarn:

yarn add evl

Usage

const evl = require('evl');

let err = () => {
    throw new Error('An error. 😱');
};
let one = () => 1;
let two = () => 2;
let add = (a, b) => a + b;
let multiply = (a, b) => a * b;

/*
 * Simple usage
 */
let a = evl(one, two); // a is 1
let b = evl(err, two); // b is 2

/*
 * With same arguments
 */
// To call add(1, 2) or multiply(1, 2)
let c = evl(add, multiply, false)(1, 2); // c is 3 (1 + 2 from add function)
// To call err(1, 2) or multiply(1, 2)
let d = evl(err, multiply, false)(1, 2); // d is 2 (1 * 2 from multiply function)

/*
 * With different arguments
 */
// To call add(1, 2) or multiply(3, 4)
let e = evl(add, multiply, false)([1, 2], [3, 4]); // e is 3 (1 + 2 from add function)
// To call err(1, 2) or multiply(3, 4)
let f = evl(err, multiply, false)([1, 2], [3, 4]); // f is 12 (3 * 4 from multiply function)

You can also pass non-function as argument.

const evl = require('evl');
let err = () => {
    throw new Error('An error. 💩');
};

evl(err, 'I am fallback value.') // -> 'I am fallback value.'

API

evl(mainFunction, fallbackFunction, [noArguments])

mainFunction

Type: Function

A main function that you expect it to work.

If you pass non-function value to this parameter, evl will return it back. Because it can't be called. So it can't throw an error.

fallbackFunction

Type: Function

A fallback function that will work when main function throw an error.

If you pass non-function value to this parameter, evl will return that value back when main function not work.

noArguments

Type: Boolean
Default: true

If true, evl will call the main function or fallback function and return the value back instantly.
If false, evl will return the invoke function.

Invoke Function

• invoke([args...])

  Return: Any

  Call main function or fallback function with all arguments from invoke function and return the value back.

• invoke(mainFuncArgs, fallbackFuncArgs)

  Return: Any

  Call main function or fallback function with its own arguments and return the value back.

  mainFuncArgs

  Type: Array

  The arguments of main function.

  fallbackFuncArgs

  Type: Array

  The arguments of fallback function