if2

if2 A,B := if A then A else B

Table Of Contents

• Get Started
• API
• Examples

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Get Started

var if2 = require('if2');
 
if2(null, 1);
// RETURN 1
 
if2(true, 2);
// RETURN true
 
if2(null, undefined, false, 3);
// RETURN 3
 
if2(null, false, "");
// RETURN undefined

API

Basic

• if2(...)
  Return the first argument which is truthy。
  Read Truthy and Falsy: When All is Not Equal in JavaScript for more.

• if2.satisfies( Function judger, ... )
  Return the first remainder argument which satisfies the judger.
  This method may be curried. If only one argument passed, it will return something like function satisfiesJudger.

• if2.is( Function proto, ... )
  Return the first remainder argument which is an instance of proto.
  This method may be curried. If only one argument passed, it will return something like function isInstanceOfProto.

• if2.assignIfHasnot( Object foo, string propertyName, ANY value )
  Assign specified property of the object if it has not such property.

Predefined Methods

For convenience, some frequently-used judger is predfined. The usage of following methods is self-evident.

• if2.array(...)
• if2.boolean(...)
• if2.defined(...)
• if2.function(...)
• if2.number(...)
• if2.string(...)

Examples

if2 can be used with other type testing library such as is. E.g.

const if2 = require('if2');
const is = require('is');
 
if2.statisfies(is.even, 1, 3, 4);
// RETURN 4