Craft and develop a complete API corresponding to xlsx file and formula in javascript.

Hi ! We are currently using an excel spreadsheet to make some automatic calculation of 4 types of tax deductions. Everything is calculated from formulas and multiple sheets (a total of 3). It works as follow : user fill the blue cells other cells got filled automatically based on some calculations from hidden sheets. user get result for the future deduction taxes. We would like to port this on the web in order to ease the process and avoid people to buy excel or download openoffice. We need you to transform the formulas in a JS library / framework, that will could use on the website. To sum up, we want you to create one or multiple JS files with namespace and separate function. This files will expose public function in order to query and help to develop the HTML part that will render the results. This is a one time schedule thing, no other project will be based on this. We do not need you to produce any design or html wireframe. ================================================================================================================= More informations : 1. Take a look at [login to view URL] This will allow you to fill the blue area. Filling the blue area will give you some result in each cells. These result comes from calculation that are made by hidden sheets. Please play with the excel, before bid. This development needs full comprehension of the math behind the calculation. You can take a look at a part of the prototype realized here : [login to view URL] 2. Look at the other sheets Other sheets allows the calculation for each results cells. The three sheets are linked and work together. One calculate some tax, an other one calculate the income, an other one is in charge of percent, etc... There are more than 20 separate functions that only do maths : addition, percentage, sum, multiply, etc. 3. You have some default value that make all of this working. This default value should be taken as configurable value at the top of the JS lib. Thus when init the JS and if the rules are changing it will be easy to update the calculation. 4. All the logic part in the sheet should never be expose to the end user. If some developer access to the JS lib/api he should just ask for a function like : tax_without_xx_and() Thank you