WhatIfJS

Installation:

Install using yarn or npm

npm i --save whatif-js
yarn add whatif-js

Then in the entryPoint of your app/modulejust require``whatIf:

require("whatif-js");

And that's it, nothing more needed for setup. Everything is handled by the module itself.

Usage

WhatIf

WhatIf is an expression for invoking an action when the given value is not-null, not-undefined and true.

The whatIffunction has three parameters:

1. given - the value

2. action - the action to perform if the given value is not-null, not-undefined and true.

3. actionWhatIfNot - (optional) - the action to perform in case the given value returns false.

Examples:

The most basic (and useless) example would be:

let obj = { name: "Awesome App", type: "App" };
obj = obj.whatIf(obj.type === "App", function() {
  this["description"] = "I am an awesome app.";
});
//output =
//{
//  name: 'Awesome App',
//  type: 'App',
//  description: 'I am an awesome app.'
//}

Now let's get a little bit more complex. Usage in a builder like an Array or Stringalso works.

let array = [0, 1, 2, 3, 4, 5];
array = array
  .whatIf(array.length === 6, ctx => {
    return ctx.concat(6, 7, 8, 9);
  })
  .slice(2, 4)
  .join(",");
//output = 2,3,4,5,6,7,8,9

WhatIf can also be used directly with booleanslike so:

function workingWithBoolean(stopWork) {
  stopWork.whatIf(function() {
    console.log("Stop all the work!");
  });
}

Now coming to the the more complex example. Using WhatIf with functions.

There are two ways of using WhatIf with functions, the first is more simple:

function calculateSimple(doMultiplication, doDivision) {
  //three methods for three mathematical operations
  function add(...params) {
    return params.reduce((p, c) => p + c);
  }
  function multiply(...params) {
    return params.reduce((p, c) => p * c);
  }
  function divide(...params) {
    return params.reduce((p, c) => p / c);
  }

  //the values to work with
  let paramaters = [21, 23, 41, 51, 5, 1];

  //the result
  let result = add //perform add if both parameters are false
    .whatIf(doMultiplication, multiply) //this will only be executed if doDivision=false & doMultiplication=true
    .whatIf(doDivision, divide) //if doDivision=true, it will always take precedence no matter the value of doMultiplication
    .call(this, ...paramaters); //the final function call
  return result;
}

We can use the above function calculateSimplein the following three ways:

calculateSimple(false, false); //142
calculateSimple(false, true); //0.0000873307965816231
calculateSimple(true, false); //5049765
calculateSimple(true, true); //0.0000873307965816231

More complex example includes performing DMAS (Division, Multiplication, Addition, Subtraction) on a stringusing only the power ofWhatIf. See the full example here

WhatIfNotNull

whatIfNotNull is an expression for invoking an action when the target object is not null.

let person = getPersonByUsername("John Doe");
person.whatIfNotNull(
    function() {
      console.log("person is not null.");
    },
    function() {
      console.log("person is null");
    }
);

WhatIfNotUndefined

whatIfNotUndefined is exactly like whatIfNotNullbut it checks whether the object is undefined or not.

WhatIf With Different Return Type

In cases where you want a different return type then the input you can use whatIf like this:

let stringLength = "i am a string".whatIf(getLength, function() {
  return this.length;
});

WhatIfNotNullOrEmpty

An expression for invoking an action when the given array is not null and not empty. If the array is null or empty, actionWhatIfNot will be invoked instead of the action.

anyArray.whatIfNotNullOrEmpty(
  function() {
    console.log("array is not null or empty.");
  },
  function() {
    console.log("array is null or empty");
  }
);

Using Arrow Functions

All functions of whatIfare usable with arrow functions like so:

anyArray.whatIfNotNullOrEmpty(
  ctx => console.log("array is not null or empty."),
  ctx => console.log("array is null or empty")
);

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License

Copyright 2019 thecodrr (Abdullah Atta)

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.