ml-number

Mojaloop Number Library implementation that handles decimal processing of amounts/numbers

Getting Started

To use the ml-number library you need to add it as a dependency to your project with the following:

npm install @mojaloop/ml-number

Usage

To create a new instance of the MLNumber class(returns instance of MLNumber):

const MLNumber = require('@mojaloop/ml-number')
const mlNumber = new MLNumber(6) // can be instantiated with a number
const mlNumber2 = new MLNumber('6') // can be instantiated with a string
const mlNumber3 = new MLNumber(mlNumber2) // can be instantiated with a MLNumber

Use different function(returns new instance of new MLNumber):

const MLNumber = require('@mojaloop/ml-number')

const originalValue = new MLNumber(6) // = "{"MLNumber": "6"}"

const additionResult = originalValue.add(12) // = "{"MLNumber": "18"}"

const multiplyResult = originalValue.multiply('12') // = "{"MLNumber": "72"}"

const divisionResult = originalValue.divide(2) // = "{"MLNumber": "3"}"

const subtractionResult = originalValue.subtract('2') // = "{"MLNumber": "4"}"

const mixedFunctionsValuesResult = new MLNumber('2').add(originalValue).sumList([additionResult, 5]) // = "{"MLNumber": "31"}"

const differentFunctionsResult = originalValue.add(2).multiply(3).divide(2).subtract(2) // = "{"MLNumber": "10"}"

const sumListResult = originalValue.sumList([2,3]) // = "{"MLNumber": "11"}"

const toStringResult = additionResult.toString() // = "18"

const toNumberResult = multiplyResult.toNumber() // = 72

const toFixedResult = divisionResult.toFixed() // = "3.0000"

const toFixedWithDecimalPlaceResult = subtractionResult.toFixed(7) // = "4.0000000"

const shifted = new MLNumber('0123').shiftedBy(-4) // = "{"MLNumber": "0.0123"}"

Running the tests

To run the unit tests locally

npm test

To run the test coverage tests locally

npm run test:coverage

Auditing Dependencies

We use audit-ci along with npm audit to check dependencies for node vulnerabilities, and keep track of resolved dependencies with an audit-ci.jsonc file.

To start a new resolution process, run:

npm run audit:fix

You can then check to see if the CI will pass based on the current dependencies with:

npm run audit:check

The audit-ci.jsonc contains any audit-exceptions that cannot be fixed to ensure that CircleCI will build correctly.

Automated Releases

As part of our CI/CD process, we use a combination of CircleCI, standard-version npm package and github-release CircleCI orb to automatically trigger our releases and image builds. This process essentially mimics a manual tag and release.

On a merge to master, CircleCI is configured to use the mojaloopci github account to push the latest generated CHANGELOG and package version number.

Once those changes are pushed, CircleCI will pull the updated master, tag and push a release triggering another subsequent build that also publishes a docker image.

Potential problems

• There is a case where the merge to master workflow will resolve successfully, triggering a release. Then that tagged release workflow subsequently failing due to the image scan, audit check, vulnerability check or other "live" checks.

  This will leave master without an associated published build. Fixes that require a new merge will essentially cause a skip in version number or require a clean up of the master branch to the commit before the CHANGELOG and bump.

  This may be resolved by relying solely on the previous checks of the merge to master workflow to assume that our tagged release is of sound quality. We are still mulling over this solution since catching bugs/vulnerabilities/etc earlier is a boon.

• It is unknown if a race condition might occur with multiple merges with master in quick succession, but this is a suspected edge case.

Additional Notes

n/a