Implement 'M.find()'

[fave77]

Do the checklist before filing the issue:

• [x] Do you have Node.js and all the relevant dev-dependencies installed?
• [ ] Is this a bug fix?
• [x] Is this an enhancement?
• [x] Is this a feature request?

NOTE: Provide a clear and concise description of the feature that needs to be added! Or if its a bug, then provide the necessary steps to reproduce it along with screenshots.

• Give your answer below:

---

• Function: M.find()
• Argument: String
• Return-Type: Function
• Usage:

  
  const factorial = M.find('factorial');    /* returns the function for 'finding' the nth-factorial */
  factorial(5);    /* 120 */

/ OR /

M.find('factorial')(7); / 5040 / M.find('bell')(5); / 52 /

- Implementation:
  - Inside the module **find**, provide an _index.js_:
  ```js
  module.exports = arg => {
    /* first validate the argument here ... */
   /* return the corresponding function */
    return require(`../${arg}`).find;
  };

• Changes:
  • Test this feature by only tweaking factorial module i.e. you need to change line 21:

    exports.factorial = num => {
    /* should change into */
    exports.find = num => {

  • Similarly, also make changes in factorial-spec.js, line 2:

    factorial = require('../src/factorial').factorial;
    /* should change into */
    factorial = require('../src/factorial').find;

  • Accordingly make changes in src/index.js and remove any factorial hooks and add find module via which we can access factorial or any nth-number.

[NOTE: M.factorial() will be deprecated after resolving this issue and similarly, within the next few weeks, we're gonna migrate to M.find() for finding all nth-number modules. Do not change any other nth number module for now, just stick with factorial. A separate issue will be opened for that once this one gets successfully resolved.]

[Manvityagi]

Can I work on this? @pbiswas101

[fave77]

@Manvityagi You're assigned!