Feature/73 default json mapper response

[maryiabydanova]

Resolves #73

• Introduce factory similar like in splitMapper:
  • define JsonMapper type
  • wrap mapper into factory function
  • implement setting default
  • produce and export default jsonMapper created by the factory
• prove that it works by covering new changes by unit tests
• describe jsonMapper api in a Readme.md - docs: added jsonMapper overview siemienik.github.io#21

[codecov]

Codecov Report

Merging #201 (f66674c) into master (faebc52) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #201   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           55        56    +1     
  Lines         1087      1098   +11     
  Branches       154       134   -20     
=========================================
+ Hits          1087      1098   +11     

Flag	Coverage Δ
xlsx-import	100.00% <100.00%> (ø)
xlsx-renderer	100.00% <ø> (ø)

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Impacted Files	Coverage Δ
packages/xlsx-import/src/mappers/jsonMapper.ts	100.00% <100.00%> (ø)
.../xlsx-import/tests/unit/mappers/jsonMapper.test.ts	100.00% <100.00%> (ø)
...lsx-import/tests/unit/mappers/stringMapper.test.ts	100.00% <100.00%> (ø)

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[Siemienik]

Hi @maryiabydanova
Thank you for the contribution, That's great!

I added some comments with proposals to update typings. These will enable TypeScript features:

interface IPerson {
    name: string
}

const nobody:IPerson = {name:'nobody'};
const personMapper = jsonMapper.default(nobody);
const person = personMapper<IPerson>('incorrect'); // person is always IPerson
// person.name === 'nobody'
const person2 = personMapper<IPerson>('{name:"Pablo"}'); // person2 is always IPerson
// person.name === 'Pablo'

Or with type discrimination:

interface IPerson {
    name:string
}
const invalidJson = new Error('The parsed json was invalid.');

const personMapper = jsonMapper.default<typeof invalidJson>(invalidJson);
const person = personMapper<IPerson>('incorrect');
if(person instanceof Error){
    throw person;
}
doSomethingWithPerson(person);

Would you mind running two commands in packages/xlsx-import?

npm run lint:fix
npm run format

They care about formatting.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[Siemienik]

LGTM

[Siemienik]

Thank you @maryiabydanova, it works great!

I'm going to publish this release up to 20th Dec.